slice - Rust
Expand description
A dynamically-sized view into a contiguous sequence, [T].
Contiguous here means that elements are laid out so that every element is the same distance from its neighbors.
See also the std::slice module.
Slices are a view into a block of memory represented as a pointer and a length.
// slicing a Vec
let vec = vec![1, 2, 3];
let int_slice = &vec[..];
// coercing an array to a slice
let str_slice: &[&str] = &["one", "two", "three"];
Slices are either mutable or shared. The shared slice type is &[T],
while the mutable slice type is &mut [T], where T represents the element
type. For example, you can mutate the block of memory that a mutable slice
points to:
let mut x = [1, 2, 3];
let x = &mut x[..]; // Take a full slice of `x`.
x[1] = 7;
assert_eq!(x, &[1, 7, 3]);
It is possible to slice empty subranges of slices by using empty ranges (including slice.len()..slice.len()):
let x = [1, 2, 3];
let empty = &x[0..0]; // subslice before the first element
assert_eq!(empty, &[]);
let empty = &x[..0]; // same as &x[0..0]
assert_eq!(empty, &[]);
let empty = &x[1..1]; // empty subslice in the middle
assert_eq!(empty, &[]);
let empty = &x[3..3]; // subslice after the last element
assert_eq!(empty, &[]);
let empty = &x[3..]; // same as &x[3..3]
assert_eq!(empty, &[]);
It is not allowed to use subranges that start with lower bound bigger than slice.len():
ⓘ
let x = vec![1, 2, 3];
let _ = &x[4..4];
As slices store the length of the sequence they refer to, they have twice
the size of pointers to Sized types.
Also see the reference on
dynamically sized types.
let pointer_size = std::mem::size_of::<&u8>();
assert_eq!(2 * pointer_size, std::mem::size_of::<&[u8]>());
assert_eq!(2 * pointer_size, std::mem::size_of::<*const [u8]>());
assert_eq!(2 * pointer_size, std::mem::size_of::<Box<[u8]>>());
assert_eq!(2 * pointer_size, std::mem::size_of::<Rc<[u8]>>());
§ Trait Implementations
Some traits are implemented for slices if the element type implements
that trait. This includes Eq, Hash and Ord.
§ Iteration
The slices implement IntoIterator. The iterator yields references to the
slice elements.
let numbers: &[i32] = &[0, 1, 2];
for n in numbers {
println!("{n} is a number!");
}
The mutable slice yields mutable references to the elements:
let mut scores: &mut [i32] = &mut [7, 8, 9];
for score in scores {
*score += 1;
}
This iterator yields mutable references to the slice’s elements, so while
the element type of the slice is i32, the element type of the iterator is
&mut i32.
.iterand.iter_mutare the explicit methods to return the default iterators.- Further methods that return iterators are
.split,.splitn,.chunks,.windowsand more.
1.82.0 · Source
Constructs a new boxed slice with uninitialized contents.
§ Examples
let mut values = Box::<[u32]>::new_uninit_slice(3);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe {values.assume_init() };
assert_eq!(*values, [1, 2, 3])
Source
🔬This is a nightly-only experimental API. ( new_zeroed_alloc #129396)
Constructs a new boxed slice with uninitialized contents, with the memory
being filled with 0 bytes.
See MaybeUninit::zeroed for examples of correct and incorrect usage
of this method.
§ Examples
#![feature(new_zeroed_alloc)]
let values = Box::<[u32]>::new_zeroed_slice(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0])
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails.
§ Examples
#![feature(allocator_api)]
let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [1, 2, 3]);
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents, with the memory
being filled with 0 bytes. Returns an error if the allocation fails.
See MaybeUninit::zeroed for examples of correct and incorrect usage
of this method.
§ Examples
#![feature(allocator_api)]
let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0]);
Source
🔬This is a nightly-only experimental API. ( slice_as_array #133508)
Converts the boxed slice into a boxed array.
This operation does not reallocate; the underlying array of the slice is simply reinterpreted as an array type.
If N is not exactly equal to the length of self, then this method returns None.
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents in the provided allocator.
§ Examples
#![feature(allocator_api)]
use std::alloc::System;
let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [1, 2, 3])
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents in the provided allocator,
with the memory being filled with 0 bytes.
See MaybeUninit::zeroed for examples of correct and incorrect usage
of this method.
§ Examples
#![feature(allocator_api)]
use std::alloc::System;
let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0])
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents in the provided allocator. Returns an error if the allocation fails.
§ Examples
#![feature(allocator_api)]
use std::alloc::System;
let mut values = Box::<[u32], _>::try_new_uninit_slice_in(3, System)?;
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [1, 2, 3]);
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Constructs a new boxed slice with uninitialized contents in the provided allocator, with the memory
being filled with 0 bytes. Returns an error if the allocation fails.
See MaybeUninit::zeroed for examples of correct and incorrect usage
of this method.
§ Examples
#![feature(allocator_api)]
use std::alloc::System;
let values = Box::<[u32], _>::try_new_zeroed_slice_in(3, System)?;
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0]);
1.82.0 · Source
Converts to Box<[T], A>.
§ Safety
As with MaybeUninit::assume_init,
it is up to the caller to guarantee that the values
really are in an initialized state.
Calling this when the content is not yet fully initialized
causes immediate undefined behavior.
§ Examples
let mut values = Box::<[u32]>::new_uninit_slice(3);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [1, 2, 3])
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_write_slice #79995)
Copies the elements from src to self,
returning a mutable reference to the now initialized contents of self.
If T does not implement Copy, use write_clone_of_slice instead.
This is similar to slice::copy_from_slice.
§ Panics
This function will panic if the two slices have different lengths.
§ Examples
#![feature(maybe_uninit_write_slice)]
use std::mem::MaybeUninit;
let mut dst = [MaybeUninit::uninit(); 32];
let src = [0; 32];
let init = dst.write_copy_of_slice(&src);
assert_eq!(init, src);
#![feature(maybe_uninit_write_slice)]
let mut vec = Vec::with_capacity(32);
let src = [0; 16];
vec.spare_capacity_mut()[..src.len()].write_copy_of_slice(&src);
// SAFETY: we have just copied all the elements of len into the spare capacity
// the first src.len() elements of the vec are valid now.
unsafe {
vec.set_len(src.len());
}
assert_eq!(vec, src);
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_write_slice #79995)
Clones the elements from src to self,
returning a mutable reference to the now initialized contents of self.
Any already initialized elements will not be dropped.
If T implements Copy, use write_copy_of_slice instead.
This is similar to slice::clone_from_slice but does not drop existing elements.
§ Panics
This function will panic if the two slices have different lengths, or if the implementation of Clone panics.
If there is a panic, the already cloned elements will be dropped.
§ Examples
#![feature(maybe_uninit_write_slice)]
use std::mem::MaybeUninit;
let mut dst = [const { MaybeUninit::uninit() }; 5];
let src = ["wibbly", "wobbly", "timey", "wimey", "stuff"].map(|s| s.to_string());
let init = dst.write_clone_of_slice(&src);
assert_eq!(init, src);
#![feature(maybe_uninit_write_slice)]
let mut vec = Vec::with_capacity(32);
let src = ["rust", "is", "a", "pretty", "cool", "language"].map(|s| s.to_string());
vec.spare_capacity_mut()[..src.len()].write_clone_of_slice(&src);
// SAFETY: we have just cloned all the elements of len into the spare capacity
// the first src.len() elements of the vec are valid now.
unsafe {
vec.set_len(src.len());
}
assert_eq!(vec, src);
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_as_bytes #93092)
Returns the contents of this MaybeUninit as a slice of potentially uninitialized bytes.
Note that even if the contents of a MaybeUninit have been initialized, the value may still
contain padding bytes which are left uninitialized.
§ Examples
#![feature(maybe_uninit_as_bytes, maybe_uninit_write_slice, maybe_uninit_slice)]
use std::mem::MaybeUninit;
let uninit = [MaybeUninit::new(0x1234u16), MaybeUninit::new(0x5678u16)];
let uninit_bytes = uninit.as_bytes();
let bytes = unsafe { uninit_bytes.assume_init_ref() };
let val1 = u16::from_ne_bytes(bytes[0..2].try_into().unwrap());
let val2 = u16::from_ne_bytes(bytes[2..4].try_into().unwrap());
assert_eq!(&[val1, val2], &[0x1234u16, 0x5678u16]);
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_as_bytes #93092)
Returns the contents of this MaybeUninit slice as a mutable slice of potentially
uninitialized bytes.
Note that even if the contents of a MaybeUninit have been initialized, the value may still
contain padding bytes which are left uninitialized.
§ Examples
#![feature(maybe_uninit_as_bytes, maybe_uninit_write_slice, maybe_uninit_slice)]
use std::mem::MaybeUninit;
let mut uninit = [MaybeUninit::<u16>::uninit(), MaybeUninit::<u16>::uninit()];
let uninit_bytes = MaybeUninit::slice_as_bytes_mut(&mut uninit);
uninit_bytes.write_copy_of_slice(&[0x12, 0x34, 0x56, 0x78]);
let vals = unsafe { uninit.assume_init_ref() };
if cfg!(target_endian = "little") {
assert_eq!(vals, &[0x3412u16, 0x7856u16]);
} else {
assert_eq!(vals, &[0x1234u16, 0x5678u16]);
}
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_slice #63569)
Drops the contained values in place.
§ Safety
It is up to the caller to guarantee that every MaybeUninit<T> in the slice
really is in an initialized state. Calling this when the content is not yet
fully initialized causes undefined behavior.
On top of that, all additional invariants of the type T must be
satisfied, as the Drop implementation of T (or its members) may
rely on this. For example, setting a Vec<T> to an invalid but
non-null address makes it initialized (under the current implementation;
this does not constitute a stable guarantee), because the only
requirement the compiler knows about it is that the data pointer must be
non-null. Dropping such a Vec<T> however will cause undefined
behaviour.
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_slice #63569)
Gets a shared reference to the contained value.
§ Safety
Calling this when the content is not yet fully initialized causes undefined
behavior: it is up to the caller to guarantee that every MaybeUninit<T> in
the slice really is in an initialized state.
Source
🔬This is a nightly-only experimental API. ( maybe_uninit_slice #63569)
Gets a mutable (unique) reference to the contained value.
§ Safety
Calling this when the content is not yet fully initialized causes undefined
behavior: it is up to the caller to guarantee that every MaybeUninit<T> in the
slice really is in an initialized state. For instance, .assume_init_mut() cannot
be used to initialize a MaybeUninit slice.
Source
🔬This is a nightly-only experimental API. ( ascii_char #110998)
Views this slice of ASCII characters as a UTF-8 str.
Source
🔬This is a nightly-only experimental API. ( ascii_char #110998)
Views this slice of ASCII characters as a slice of u8 bytes.
1.23.0 (const: 1.74.0) · Source
Checks if all bytes in this slice are within the ASCII range.
Source
🔬This is a nightly-only experimental API. ( ascii_char #110998)
Source
🔬This is a nightly-only experimental API. ( ascii_char #110998)
Converts this slice of bytes into a slice of ASCII characters, without checking whether they’re valid.
§ Safety
Every byte in the slice must be in 0..=127, or else this is UB.
1.23.0 (const: unstable) · Source
Checks that two slices are an ASCII case-insensitive match.
Same as to_ascii_lowercase(a) == to_ascii_lowercase(b),
but without allocating and copying temporaries.
1.23.0 (const: 1.84.0) · Source
Converts this slice to its ASCII upper case equivalent in-place.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.
To return a new uppercased value without modifying the existing one, use
to_ascii_uppercase.
1.23.0 (const: 1.84.0) · Source
Converts this slice to its ASCII lower case equivalent in-place.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.
To return a new lowercased value without modifying the existing one, use
to_ascii_lowercase.
1.60.0 · Source
Returns an iterator that produces an escaped version of this slice, treating it as an ASCII string.
§ Examples
let s = b"0\t\r\n'\"\\\x9d";
let escaped = s.escape_ascii().to_string();
assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");
1.80.0 (const: 1.80.0) · Source
Returns a byte slice with leading ASCII whitespace bytes removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace.
§ Examples
assert_eq!(b" \t hello world\n".trim_ascii_start(), b"hello world\n");
assert_eq!(b" ".trim_ascii_start(), b"");
assert_eq!(b"".trim_ascii_start(), b"");
1.80.0 (const: 1.80.0) · Source
Returns a byte slice with trailing ASCII whitespace bytes removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace.
§ Examples
assert_eq!(b"\r hello world\n ".trim_ascii_end(), b"\r hello world");
assert_eq!(b" ".trim_ascii_end(), b"");
assert_eq!(b"".trim_ascii_end(), b"");
1.80.0 (const: 1.80.0) · Source
Returns a byte slice with leading and trailing ASCII whitespace bytes removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace.
§ Examples
assert_eq!(b"\r hello world\n ".trim_ascii(), b"hello world");
assert_eq!(b" ".trim_ascii(), b"");
assert_eq!(b"".trim_ascii(), b"");
1.0.0 (const: 1.39.0) · Source
Returns the number of elements in the slice.
§ Examples
let a = [1, 2, 3];
assert_eq!(a.len(), 3);
1.0.0 (const: 1.39.0) · Source
Returns true if the slice has a length of 0.
§ Examples
let a = [1, 2, 3];
assert!(!a.is_empty());
let b: &[i32] = &[];
assert!(b.is_empty());
1.0.0 (const: 1.56.0) · Source
Returns the first element of the slice, or None if it is empty.
§ Examples
let v = [10, 40, 30];
assert_eq!(Some(&10), v.first());
let w: &[i32] = &[];
assert_eq!(None, w.first());
1.0.0 (const: 1.83.0) · Source
Returns a mutable reference to the first element of the slice, or None if it is empty.
§ Examples
let x = &mut [0, 1, 2];
if let Some(first) = x.first_mut() {
*first = 5;
}
assert_eq!(x, &[5, 1, 2]);
let y: &mut [i32] = &mut [];
assert_eq!(None, y.first_mut());
1.5.0 (const: 1.56.0) · Source
Returns the first and all the rest of the elements of the slice, or None if it is empty.
§ Examples
let x = &[0, 1, 2];
if let Some((first, elements)) = x.split_first() {
assert_eq!(first, &0);
assert_eq!(elements, &[1, 2]);
}
1.5.0 (const: 1.83.0) · Source
Returns the first and all the rest of the elements of the slice, or None if it is empty.
§ Examples
let x = &mut [0, 1, 2];
if let Some((first, elements)) = x.split_first_mut() {
*first = 3;
elements[0] = 4;
elements[1] = 5;
}
assert_eq!(x, &[3, 4, 5]);
1.5.0 (const: 1.56.0) · Source
Returns the last and all the rest of the elements of the slice, or None if it is empty.
§ Examples
let x = &[0, 1, 2];
if let Some((last, elements)) = x.split_last() {
assert_eq!(last, &2);
assert_eq!(elements, &[0, 1]);
}
1.5.0 (const: 1.83.0) · Source
Returns the last and all the rest of the elements of the slice, or None if it is empty.
§ Examples
let x = &mut [0, 1, 2];
if let Some((last, elements)) = x.split_last_mut() {
*last = 3;
elements[0] = 4;
elements[1] = 5;
}
assert_eq!(x, &[4, 5, 3]);
1.0.0 (const: 1.56.0) · Source
Returns the last element of the slice, or None if it is empty.
§ Examples
let v = [10, 40, 30];
assert_eq!(Some(&30), v.last());
let w: &[i32] = &[];
assert_eq!(None, w.last());
1.0.0 (const: 1.83.0) · Source
Returns a mutable reference to the last item in the slice, or None if it is empty.
§ Examples
let x = &mut [0, 1, 2];
if let Some(last) = x.last_mut() {
*last = 10;
}
assert_eq!(x, &[0, 1, 10]);
let y: &mut [i32] = &mut [];
assert_eq!(None, y.last_mut());
1.77.0 (const: 1.77.0) · Source
Returns an array reference to the first N items in the slice.
If the slice is not at least N in length, this will return None.
§ Examples
let u = [10, 40, 30];
assert_eq!(Some(&[10, 40]), u.first_chunk::<2>());
let v: &[i32] = &[10];
assert_eq!(None, v.first_chunk::<2>());
let w: &[i32] = &[];
assert_eq!(Some(&[]), w.first_chunk::<0>());
1.77.0 (const: 1.83.0) · Source
Returns a mutable array reference to the first N items in the slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &mut [0, 1, 2];
if let Some(first) = x.first_chunk_mut::<2>() {
first[0] = 5;
first[1] = 4;
}
assert_eq!(x, &[5, 4, 2]);
assert_eq!(None, x.first_chunk_mut::<4>());
1.77.0 (const: 1.77.0) · Source
Returns an array reference to the first N items in the slice and the remaining slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &[0, 1, 2];
if let Some((first, elements)) = x.split_first_chunk::<2>() {
assert_eq!(first, &[0, 1]);
assert_eq!(elements, &[2]);
}
assert_eq!(None, x.split_first_chunk::<4>());
1.77.0 (const: 1.83.0) · Source
Returns a mutable array reference to the first N items in the slice and the remaining
slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &mut [0, 1, 2];
if let Some((first, elements)) = x.split_first_chunk_mut::<2>() {
first[0] = 3;
first[1] = 4;
elements[0] = 5;
}
assert_eq!(x, &[3, 4, 5]);
assert_eq!(None, x.split_first_chunk_mut::<4>());
1.77.0 (const: 1.77.0) · Source
Returns an array reference to the last N items in the slice and the remaining slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &[0, 1, 2];
if let Some((elements, last)) = x.split_last_chunk::<2>() {
assert_eq!(elements, &[0]);
assert_eq!(last, &[1, 2]);
}
assert_eq!(None, x.split_last_chunk::<4>());
1.77.0 (const: 1.83.0) · Source
Returns a mutable array reference to the last N items in the slice and the remaining
slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &mut [0, 1, 2];
if let Some((elements, last)) = x.split_last_chunk_mut::<2>() {
last[0] = 3;
last[1] = 4;
elements[0] = 5;
}
assert_eq!(x, &[5, 3, 4]);
assert_eq!(None, x.split_last_chunk_mut::<4>());
1.77.0 (const: 1.80.0) · Source
Returns an array reference to the last N items in the slice.
If the slice is not at least N in length, this will return None.
§ Examples
let u = [10, 40, 30];
assert_eq!(Some(&[40, 30]), u.last_chunk::<2>());
let v: &[i32] = &[10];
assert_eq!(None, v.last_chunk::<2>());
let w: &[i32] = &[];
assert_eq!(Some(&[]), w.last_chunk::<0>());
1.77.0 (const: 1.83.0) · Source
Returns a mutable array reference to the last N items in the slice.
If the slice is not at least N in length, this will return None.
§ Examples
let x = &mut [0, 1, 2];
if let Some(last) = x.last_chunk_mut::<2>() {
last[0] = 10;
last[1] = 20;
}
assert_eq!(x, &[0, 10, 20]);
assert_eq!(None, x.last_chunk_mut::<4>());
1.0.0 · Source
Returns a reference to an element or subslice depending on the type of index.
- If given a position, returns a reference to the element at that
position or
Noneif out of bounds. - If given a range, returns the subslice corresponding to that range,
or
Noneif out of bounds.
§ Examples
let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));
1.0.0 · Source
Returns a mutable reference to an element or subslice depending on the
type of index (see get) or None if the index is out of bounds.
§ Examples
let x = &mut [0, 1, 2];
if let Some(elem) = x.get_mut(1) {
*elem = 42;
}
assert_eq!(x, &[0, 42, 2]);
1.0.0 · Source
Returns a reference to an element or subslice, without doing bounds checking.
For a safe alternative see get.
§ Safety
Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.
You can think of this like .get(index).unwrap_unchecked(). It’s UB
to call .get_unchecked(len), even if you immediately convert to a
pointer. And it’s UB to call .get_unchecked(..len + 1),
.get_unchecked(..=len), or similar.
§ Examples
let x = &[1, 2, 4];
unsafe {
assert_eq!(x.get_unchecked(1), &2);
}
1.0.0 · Source
Returns a mutable reference to an element or subslice, without doing bounds checking.
For a safe alternative see get_mut.
§ Safety
Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.
You can think of this like .get_mut(index).unwrap_unchecked(). It’s
UB to call .get_unchecked_mut(len), even if you immediately convert
to a pointer. And it’s UB to call .get_unchecked_mut(..len + 1),
.get_unchecked_mut(..=len), or similar.
§ Examples
let x = &mut [1, 2, 4];
unsafe {
let elem = x.get_unchecked_mut(1);
*elem = 13;
}
assert_eq!(x, &[1, 13, 4]);
1.0.0 (const: 1.32.0) · Source
Returns a raw pointer to the slice’s buffer.
The caller must ensure that the slice outlives the pointer this function returns, or else it will end up dangling.
The caller must also ensure that the memory the pointer (non-transitively) points to
is never written to (except inside an UnsafeCell) using this pointer or any pointer
derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.
Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.
§ Examples
let x = &[1, 2, 4];
let x_ptr = x.as_ptr();
unsafe {
for i in 0..x.len() {
assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
}
}
1.0.0 (const: 1.61.0) · Source
Returns an unsafe mutable pointer to the slice’s buffer.
The caller must ensure that the slice outlives the pointer this function returns, or else it will end up dangling.
Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.
§ Examples
let x = &mut [1, 2, 4];
let x_ptr = x.as_mut_ptr();
unsafe {
for i in 0..x.len() {
*x_ptr.add(i) += 2;
}
}
assert_eq!(x, &[3, 4, 6]);
1.48.0 (const: 1.61.0) · Source
Returns the two raw pointers spanning the slice.
The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.
See as_ptr for warnings on using these pointers. The end pointer
requires extra caution, as it does not point to a valid element in the
slice.
This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.
It can also be useful to check if a pointer to an element refers to an element of this slice:
let a = [1, 2, 3];
let x = &a[1] as *const _;
let y = &5 as *const _;
assert!(a.as_ptr_range().contains(&x));
assert!(!a.as_ptr_range().contains(&y));
1.48.0 (const: 1.61.0) · Source
Returns the two unsafe mutable pointers spanning the slice.
The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.
See as_mut_ptr for warnings on using these pointers. The end
pointer requires extra caution, as it does not point to a valid element
in the slice.
This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.
Source
🔬This is a nightly-only experimental API. ( slice_as_array #133508)
Gets a reference to the underlying array.
If N is not exactly equal to the length of self, then this method returns None.
Source
🔬This is a nightly-only experimental API. ( slice_as_array #133508)
Gets a mutable reference to the slice’s underlying array.
If N is not exactly equal to the length of self, then this method returns None.
1.0.0 (const: 1.85.0) · Source
Swaps two elements in the slice.
If a equals to b, it’s guaranteed that elements won’t change value.
§ Arguments
- a - The index of the first element
- b - The index of the second element
§ Panics
Panics if a or b are out of bounds.
§ Examples
let mut v = ["a", "b", "c", "d", "e"];
v.swap(2, 4);
assert!(v == ["a", "b", "e", "d", "c"]);
Source
🔬This is a nightly-only experimental API. ( slice_swap_unchecked #88539)
Swaps two elements in the slice, without doing bounds checking.
For a safe alternative see swap.
§ Arguments
- a - The index of the first element
- b - The index of the second element
§ Safety
Calling this method with an out-of-bounds index is undefined behavior.
The caller has to ensure that a < self.len() and b < self.len().
§ Examples
#![feature(slice_swap_unchecked)]
let mut v = ["a", "b", "c", "d"];
// SAFETY: we know that 1 and 3 are both indices of the slice
unsafe { v.swap_unchecked(1, 3) };
assert!(v == ["a", "d", "c", "b"]);
1.0.0 (const: unstable) · Source
Reverses the order of elements in the slice, in place.
§ Examples
let mut v = [1, 2, 3];
v.reverse();
assert!(v == [3, 2, 1]);
1.0.0 · Source
Returns an iterator over the slice.
The iterator yields all items from start to end.
§ Examples
let x = &[1, 2, 4];
let mut iterator = x.iter();
assert_eq!(iterator.next(), Some(&1));
assert_eq!(iterator.next(), Some(&2));
assert_eq!(iterator.next(), Some(&4));
assert_eq!(iterator.next(), None);
1.0.0 · Source
Returns an iterator that allows modifying each value.
The iterator yields all items from start to end.
§ Examples
let x = &mut [1, 2, 4];
for elem in x.iter_mut() {
*elem += 2;
}
assert_eq!(x, &[3, 4, 6]);
1.0.0 · Source
Returns an iterator over all contiguous windows of length
size. The windows overlap. If the slice is shorter than
size, the iterator returns no values.
§ Panics
Panics if size is zero.
§ Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.windows(3);
assert_eq!(iter.next().unwrap(), &['l', 'o', 'r']);
assert_eq!(iter.next().unwrap(), &['o', 'r', 'e']);
assert_eq!(iter.next().unwrap(), &['r', 'e', 'm']);
assert!(iter.next().is_none());
If the slice is shorter than size:
let slice = ['f', 'o', 'o'];
let mut iter = slice.windows(4);
assert!(iter.next().is_none());
Because the Iterator trait cannot represent the required lifetimes,
there is no windows_mut analog to windows;
[0,1,2].windows_mut(2).collect() would violate the rules of references
(though a LendingIterator analog is possible). You can sometimes use
Cell::as_slice_of_cells in
conjunction with windows instead:
use std::cell::Cell;
let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
let slice = &mut array[..];
let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
for w in slice_of_cells.windows(3) {
Cell::swap(&w[0], &w[2]);
}
assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);
1.0.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the
beginning of the slice.
The chunks are slices and do not overlap. If chunk_size does not divide the length of the
slice, then the last chunk will not have length chunk_size.
See chunks_exact for a variant of this iterator that returns chunks of always exactly
chunk_size elements, and rchunks for the same iterator but starting at the end of the
slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.chunks(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert_eq!(iter.next().unwrap(), &['m']);
assert!(iter.next().is_none());
1.0.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the
beginning of the slice.
The chunks are mutable slices, and do not overlap. If chunk_size does not divide the
length of the slice, then the last chunk will not have length chunk_size.
See chunks_exact_mut for a variant of this iterator that returns chunks of always
exactly chunk_size elements, and rchunks_mut for the same iterator but starting at
the end of the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
for chunk in v.chunks_mut(2) {
for elem in chunk.iter_mut() {
*elem += count;
}
count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 3]);
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the
beginning of the slice.
The chunks are slices and do not overlap. If chunk_size does not divide the length of the
slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved
from the remainder function of the iterator.
Due to each chunk having exactly chunk_size elements, the compiler can often optimize the
resulting code better than in the case of chunks.
See chunks for a variant of this iterator that also returns the remainder as a smaller
chunk, and rchunks_exact for the same iterator but starting at the end of the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.chunks_exact(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['m']);
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the
beginning of the slice.
The chunks are mutable slices, and do not overlap. If chunk_size does not divide the
length of the slice, then the last up to chunk_size-1 elements will be omitted and can be
retrieved from the into_remainder function of the iterator.
Due to each chunk having exactly chunk_size elements, the compiler can often optimize the
resulting code better than in the case of chunks_mut.
See chunks_mut for a variant of this iterator that also returns the remainder as a
smaller chunk, and rchunks_exact_mut for the same iterator but starting at the end of
the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
for chunk in v.chunks_exact_mut(2) {
for elem in chunk.iter_mut() {
*elem += count;
}
count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 0]);
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
assuming that there’s no remainder.
§ Safety
This may only be called when
- The slice splits exactly into
N-element chunks (akaself.len() % N == 0). N != 0.
§ Examples
#![feature(slice_as_chunks)]
let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &[[char; 1]] =
// SAFETY: 1-element chunks never have remainder
unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &[[char; 3]] =
// SAFETY: The slice length (6) is a multiple of 3
unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);
// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
starting at the beginning of the slice,
and a remainder slice with length strictly less than N.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (chunks, remainder) = slice.as_chunks();
assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
assert_eq!(remainder, &['m']);
If you expect the slice to be an exact multiple, you can combine
let- else with an empty slice pattern:
#![feature(slice_as_chunks)]
let slice = ['R', 'u', 's', 't'];
let (chunks, []) = slice.as_chunks::<2>() else {
panic!("slice didn't have even length")
};
assert_eq!(chunks, &[['R', 'u'], ['s', 't']]);
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
starting at the end of the slice,
and a remainder slice with length strictly less than N.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (remainder, chunks) = slice.as_rchunks();
assert_eq!(remainder, &['l']);
assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);
Source
🔬This is a nightly-only experimental API. ( array_chunks #74985)
Returns an iterator over N elements of the slice at a time, starting at the
beginning of the slice.
The chunks are array references and do not overlap. If N does not divide the
length of the slice, then the last up to N-1 elements will be omitted and can be
retrieved from the remainder function of the iterator.
This method is the const generic equivalent of chunks_exact.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(array_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.array_chunks();
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['m']);
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
assuming that there’s no remainder.
§ Safety
This may only be called when
- The slice splits exactly into
N-element chunks (akaself.len() % N == 0). N != 0.
§ Examples
#![feature(slice_as_chunks)]
let slice: &mut [char] = &mut ['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &mut [[char; 1]] =
// SAFETY: 1-element chunks never have remainder
unsafe { slice.as_chunks_unchecked_mut() };
chunks[0] = ['L'];
assert_eq!(chunks, &[['L'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &mut [[char; 3]] =
// SAFETY: The slice length (6) is a multiple of 3
unsafe { slice.as_chunks_unchecked_mut() };
chunks[1] = ['a', 'x', '?'];
assert_eq!(slice, &['L', 'o', 'r', 'a', 'x', '?']);
// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked_mut() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked_mut() // Zero-length chunks are never allowed
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
starting at the beginning of the slice,
and a remainder slice with length strictly less than N.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(slice_as_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
let (chunks, remainder) = v.as_chunks_mut();
remainder[0] = 9;
for chunk in chunks {
*chunk = [count; 2];
count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 9]);
Source
🔬This is a nightly-only experimental API. ( slice_as_chunks #74985)
Splits the slice into a slice of N-element arrays,
starting at the end of the slice,
and a remainder slice with length strictly less than N.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(slice_as_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
let (remainder, chunks) = v.as_rchunks_mut();
remainder[0] = 9;
for chunk in chunks {
*chunk = [count; 2];
count += 1;
}
assert_eq!(v, &[9, 1, 1, 2, 2]);
Source
🔬This is a nightly-only experimental API. ( array_chunks #74985)
Returns an iterator over N elements of the slice at a time, starting at the
beginning of the slice.
The chunks are mutable array references and do not overlap. If N does not divide
the length of the slice, then the last up to N-1 elements will be omitted and
can be retrieved from the into_remainder function of the iterator.
This method is the const generic equivalent of chunks_exact_mut.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(array_chunks)]
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
for chunk in v.array_chunks_mut() {
*chunk = [count; 2];
count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 0]);
Source
🔬This is a nightly-only experimental API. ( array_windows #75027)
Returns an iterator over overlapping windows of N elements of a slice,
starting at the beginning of the slice.
This is the const generic equivalent of windows.
If N is greater than the size of the slice, it will return no windows.
§ Panics
Panics if N is zero. This check will most probably get changed to a compile time
error before this method gets stabilized.
§ Examples
#![feature(array_windows)]
let slice = [0, 1, 2, 3];
let mut iter = slice.array_windows();
assert_eq!(iter.next().unwrap(), &[0, 1]);
assert_eq!(iter.next().unwrap(), &[1, 2]);
assert_eq!(iter.next().unwrap(), &[2, 3]);
assert!(iter.next().is_none());
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the end
of the slice.
The chunks are slices and do not overlap. If chunk_size does not divide the length of the
slice, then the last chunk will not have length chunk_size.
See rchunks_exact for a variant of this iterator that returns chunks of always exactly
chunk_size elements, and chunks for the same iterator but starting at the beginning
of the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.rchunks(2);
assert_eq!(iter.next().unwrap(), &['e', 'm']);
assert_eq!(iter.next().unwrap(), &['o', 'r']);
assert_eq!(iter.next().unwrap(), &['l']);
assert!(iter.next().is_none());
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the end
of the slice.
The chunks are mutable slices, and do not overlap. If chunk_size does not divide the
length of the slice, then the last chunk will not have length chunk_size.
See rchunks_exact_mut for a variant of this iterator that returns chunks of always
exactly chunk_size elements, and chunks_mut for the same iterator but starting at the
beginning of the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
for chunk in v.rchunks_mut(2) {
for elem in chunk.iter_mut() {
*elem += count;
}
count += 1;
}
assert_eq!(v, &[3, 2, 2, 1, 1]);
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the
end of the slice.
The chunks are slices and do not overlap. If chunk_size does not divide the length of the
slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved
from the remainder function of the iterator.
Due to each chunk having exactly chunk_size elements, the compiler can often optimize the
resulting code better than in the case of rchunks.
See rchunks for a variant of this iterator that also returns the remainder as a smaller
chunk, and chunks_exact for the same iterator but starting at the beginning of the
slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.rchunks_exact(2);
assert_eq!(iter.next().unwrap(), &['e', 'm']);
assert_eq!(iter.next().unwrap(), &['o', 'r']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['l']);
1.31.0 · Source
Returns an iterator over chunk_size elements of the slice at a time, starting at the end
of the slice.
The chunks are mutable slices, and do not overlap. If chunk_size does not divide the
length of the slice, then the last up to chunk_size-1 elements will be omitted and can be
retrieved from the into_remainder function of the iterator.
Due to each chunk having exactly chunk_size elements, the compiler can often optimize the
resulting code better than in the case of chunks_mut.
See rchunks_mut for a variant of this iterator that also returns the remainder as a
smaller chunk, and chunks_exact_mut for the same iterator but starting at the beginning
of the slice.
§ Panics
Panics if chunk_size is zero.
§ Examples
let v = &mut [0, 0, 0, 0, 0];
let mut count = 1;
for chunk in v.rchunks_exact_mut(2) {
for elem in chunk.iter_mut() {
*elem += count;
}
count += 1;
}
assert_eq!(v, &[0, 2, 2, 1, 1]);
1.77.0 · Source
Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.
The predicate is called for every pair of consecutive elements,
meaning that it is called on slice[0] and slice[1],
followed by slice[1] and slice[2], and so on.
§ Examples
let slice = &[1, 1, 1, 3, 3, 2, 2, 2];
let mut iter = slice.chunk_by(|a, b| a == b);
assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
assert_eq!(iter.next(), Some(&[3, 3][..]));
assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
assert_eq!(iter.next(), None);
This method can be used to extract the sorted subslices:
let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];
let mut iter = slice.chunk_by(|a, b| a <= b);
assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
assert_eq!(iter.next(), None);
1.77.0 · Source
Returns an iterator over the slice producing non-overlapping mutable runs of elements using the predicate to separate them.
The predicate is called for every pair of consecutive elements,
meaning that it is called on slice[0] and slice[1],
followed by slice[1] and slice[2], and so on.
§ Examples
let slice = &mut [1, 1, 1, 3, 3, 2, 2, 2];
let mut iter = slice.chunk_by_mut(|a, b| a == b);
assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
assert_eq!(iter.next(), Some(&mut [3, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
assert_eq!(iter.next(), None);
This method can be used to extract the sorted subslices:
let slice = &mut [1, 1, 2, 3, 2, 3, 2, 3, 4];
let mut iter = slice.chunk_by_mut(|a, b| a <= b);
assert_eq!(iter.next(), Some(&mut [1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 3][..]));
assert_eq!(iter.next(), Some(&mut [2, 3, 4][..]));
assert_eq!(iter.next(), None);
1.0.0 (const: 1.71.0) · Source
Divides one slice into two at an index.
The first will contain all indices from [0, mid) (excluding
the index mid itself) and the second will contain all
indices from [mid, len) (excluding the index len itself).
§ Panics
Panics if mid > len. For a non-panicking alternative see
split_at_checked.
§ Examples
let v = ['a', 'b', 'c'];
{
let (left, right) = v.split_at(0);
assert_eq!(left, []);
assert_eq!(right, ['a', 'b', 'c']);
}
{
let (left, right) = v.split_at(2);
assert_eq!(left, ['a', 'b']);
assert_eq!(right, ['c']);
}
{
let (left, right) = v.split_at(3);
assert_eq!(left, ['a', 'b', 'c']);
assert_eq!(right, []);
}
1.0.0 (const: 1.83.0) · Source
Divides one mutable slice into two at an index.
The first will contain all indices from [0, mid) (excluding
the index mid itself) and the second will contain all
indices from [mid, len) (excluding the index len itself).
§ Panics
Panics if mid > len. For a non-panicking alternative see
split_at_mut_checked.
§ Examples
let mut v = [1, 0, 3, 0, 5, 6];
let (left, right) = v.split_at_mut(2);
assert_eq!(left, [1, 0]);
assert_eq!(right, [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
1.79.0 (const: 1.77.0) · Source
Divides one slice into two at an index, without doing bounds checking.
The first will contain all indices from [0, mid) (excluding
the index mid itself) and the second will contain all
indices from [mid, len) (excluding the index len itself).
For a safe alternative see split_at.
§ Safety
Calling this method with an out-of-bounds index is undefined behavior
even if the resulting reference is not used. The caller has to ensure that
0 <= mid <= self.len().
§ Examples
let v = ['a', 'b', 'c'];
unsafe {
let (left, right) = v.split_at_unchecked(0);
assert_eq!(left, []);
assert_eq!(right, ['a', 'b', 'c']);
}
unsafe {
let (left, right) = v.split_at_unchecked(2);
assert_eq!(left, ['a', 'b']);
assert_eq!(right, ['c']);
}
unsafe {
let (left, right) = v.split_at_unchecked(3);
assert_eq!(left, ['a', 'b', 'c']);
assert_eq!(right, []);
}
1.79.0 (const: 1.83.0) · Source
Divides one mutable slice into two at an index, without doing bounds checking.
The first will contain all indices from [0, mid) (excluding
the index mid itself) and the second will contain all
indices from [mid, len) (excluding the index len itself).
For a safe alternative see split_at_mut.
§ Safety
Calling this method with an out-of-bounds index is undefined behavior
even if the resulting reference is not used. The caller has to ensure that
0 <= mid <= self.len().
§ Examples
let mut v = [1, 0, 3, 0, 5, 6];
// scoped to restrict the lifetime of the borrows
unsafe {
let (left, right) = v.split_at_mut_unchecked(2);
assert_eq!(left, [1, 0]);
assert_eq!(right, [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
}
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
1.80.0 (const: 1.80.0) · Source
Divides one slice into two at an index, returning None if the slice is
too short.
If mid ≤ len returns a pair of slices where the first will contain all
indices from [0, mid) (excluding the index mid itself) and the
second will contain all indices from [mid, len) (excluding the index
len itself).
Otherwise, if mid > len, returns None.
§ Examples
let v = [1, -2, 3, -4, 5, -6];
{
let (left, right) = v.split_at_checked(0).unwrap();
assert_eq!(left, []);
assert_eq!(right, [1, -2, 3, -4, 5, -6]);
}
{
let (left, right) = v.split_at_checked(2).unwrap();
assert_eq!(left, [1, -2]);
assert_eq!(right, [3, -4, 5, -6]);
}
{
let (left, right) = v.split_at_checked(6).unwrap();
assert_eq!(left, [1, -2, 3, -4, 5, -6]);
assert_eq!(right, []);
}
assert_eq!(None, v.split_at_checked(7));
1.80.0 (const: 1.83.0) · Source
Divides one mutable slice into two at an index, returning None if the
slice is too short.
If mid ≤ len returns a pair of slices where the first will contain all
indices from [0, mid) (excluding the index mid itself) and the
second will contain all indices from [mid, len) (excluding the index
len itself).
Otherwise, if mid > len, returns None.
§ Examples
let mut v = [1, 0, 3, 0, 5, 6];
if let Some((left, right)) = v.split_at_mut_checked(2) {
assert_eq!(left, [1, 0]);
assert_eq!(right, [3, 0, 5, 6]);
left[1] = 2;
right[1] = 4;
}
assert_eq!(v, [1, 2, 3, 4, 5, 6]);
assert_eq!(None, v.split_at_mut_checked(7));
1.0.0 · Source
Returns an iterator over subslices separated by elements that match
pred. The matched element is not contained in the subslices.
§ Examples
let slice = [10, 40, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);
assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());
If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:
let slice = [10, 40, 33];
let mut iter = slice.split(|num| num % 3 == 0);
assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[]);
assert!(iter.next().is_none());
If two matched elements are directly adjacent, an empty slice will be present between them:
let slice = [10, 6, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);
assert_eq!(iter.next().unwrap(), &[10]);
assert_eq!(iter.next().unwrap(), &[]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());
1.0.0 · Source
Returns an iterator over mutable subslices separated by elements that
match pred. The matched element is not contained in the subslices.
§ Examples
let mut v = [10, 40, 30, 20, 60, 50];
for group in v.split_mut(|num| *num % 3 == 0) {
group[0] = 1;
}
assert_eq!(v, [1, 40, 30, 1, 60, 1]);
1.51.0 · Source
Returns an iterator over subslices separated by elements that match
pred. The matched element is contained in the end of the previous
subslice as a terminator.
§ Examples
let slice = [10, 40, 33, 20];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);
assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());
If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.
let slice = [3, 10, 40, 33];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);
assert_eq!(iter.next().unwrap(), &[3]);
assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert!(iter.next().is_none());
1.51.0 · Source
Returns an iterator over mutable subslices separated by elements that
match pred. The matched element is contained in the previous
subslice as a terminator.
§ Examples
let mut v = [10, 40, 30, 20, 60, 50];
for group in v.split_inclusive_mut(|num| *num % 3 == 0) {
let terminator_idx = group.len()-1;
group[terminator_idx] = 1;
}
assert_eq!(v, [10, 40, 1, 20, 1, 1]);
1.27.0 · Source
Returns an iterator over subslices separated by elements that match
pred, starting at the end of the slice and working backwards.
The matched element is not contained in the subslices.
§ Examples
let slice = [11, 22, 33, 0, 44, 55];
let mut iter = slice.rsplit(|num| *num == 0);
assert_eq!(iter.next().unwrap(), &[44, 55]);
assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
assert_eq!(iter.next(), None);
As with split(), if the first or last element is matched, an empty
slice will be the first (or last) item returned by the iterator.
let v = &[0, 1, 1, 2, 3, 5, 8];
let mut it = v.rsplit(|n| *n % 2 == 0);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next().unwrap(), &[3, 5]);
assert_eq!(it.next().unwrap(), &[1, 1]);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next(), None);
1.27.0 · Source
Returns an iterator over mutable subslices separated by elements that
match pred, starting at the end of the slice and working
backwards. The matched element is not contained in the subslices.
§ Examples
let mut v = [100, 400, 300, 200, 600, 500];
let mut count = 0;
for group in v.rsplit_mut(|num| *num % 3 == 0) {
count += 1;
group[0] = count;
}
assert_eq!(v, [3, 400, 300, 2, 600, 1]);
1.0.0 · Source
Returns an iterator over subslices separated by elements that match
pred, limited to returning at most n items. The matched element is
not contained in the subslices.
The last element returned, if any, will contain the remainder of the slice.
§ Examples
Print the slice split once by numbers divisible by 3 (i.e., [10, 40],
[20, 60, 50]):
let v = [10, 40, 30, 20, 60, 50];
for group in v.splitn(2, |num| *num % 3 == 0) {
println!("{group:?}");
}
1.0.0 · Source
Returns an iterator over mutable subslices separated by elements that match
pred, limited to returning at most n items. The matched element is
not contained in the subslices.
The last element returned, if any, will contain the remainder of the slice.
§ Examples
let mut v = [10, 40, 30, 20, 60, 50];
for group in v.splitn_mut(2, |num| *num % 3 == 0) {
group[0] = 1;
}
assert_eq!(v, [1, 40, 30, 1, 60, 50]);
1.0.0 · Source
Returns an iterator over subslices separated by elements that match
pred limited to returning at most n items. This starts at the end of
the slice and works backwards. The matched element is not contained in
the subslices.
The last element returned, if any, will contain the remainder of the slice.
§ Examples
Print the slice split once, starting from the end, by numbers divisible
by 3 (i.e., [50], [10, 40, 30, 20]):
let v = [10, 40, 30, 20, 60, 50];
for group in v.rsplitn(2, |num| *num % 3 == 0) {
println!("{group:?}");
}
1.0.0 · Source
Returns an iterator over subslices separated by elements that match
pred limited to returning at most n items. This starts at the end of
the slice and works backwards. The matched element is not contained in
the subslices.
The last element returned, if any, will contain the remainder of the slice.
§ Examples
let mut s = [10, 40, 30, 20, 60, 50];
for group in s.rsplitn_mut(2, |num| *num % 3 == 0) {
group[0] = 1;
}
assert_eq!(s, [1, 40, 30, 20, 60, 1]);
Source
🔬This is a nightly-only experimental API. ( slice_split_once #112811)
Splits the slice on the first element that matches the specified predicate.
If any matching elements are present in the slice, returns the prefix
before the match and suffix after. The matching element itself is not
included. If no elements match, returns None.
§ Examples
#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.split_once(|&x| x == 2), Some((
&[1][..],
&[3, 2, 4][..]
)));
assert_eq!(s.split_once(|&x| x == 0), None);
Source
🔬This is a nightly-only experimental API. ( slice_split_once #112811)
Splits the slice on the last element that matches the specified predicate.
If any matching elements are present in the slice, returns the prefix
before the match and suffix after. The matching element itself is not
included. If no elements match, returns None.
§ Examples
#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.rsplit_once(|&x| x == 2), Some((
&[1, 2, 3][..],
&[4][..]
)));
assert_eq!(s.rsplit_once(|&x| x == 0), None);
1.0.0 · Source
Returns true if the slice contains an element with the given value.
This operation is O( n).
Note that if you have a sorted slice, binary_search may be faster.
§ Examples
let v = [10, 40, 30];
assert!(v.contains(&30));
assert!(!v.contains(&50));
If you do not have a &T, but some other value that you can compare
with one (for example, String implements PartialEq<str>), you can
use iter().any:
let v = [String::from("hello"), String::from("world")]; // slice of `String`
assert!(v.iter().any(|e| e == "hello")); // search with `&str`
assert!(!v.iter().any(|e| e == "hi"));
1.0.0 · Source
Returns true if needle is a prefix of the slice or equal to the slice.
§ Examples
let v = [10, 40, 30];
assert!(v.starts_with(&[10]));
assert!(v.starts_with(&[10, 40]));
assert!(v.starts_with(&v));
assert!(!v.starts_with(&[50]));
assert!(!v.starts_with(&[10, 50]));
Always returns true if needle is an empty slice:
let v = &[10, 40, 30];
assert!(v.starts_with(&[]));
let v: &[u8] = &[];
assert!(v.starts_with(&[]));
1.0.0 · Source
Returns true if needle is a suffix of the slice or equal to the slice.
§ Examples
let v = [10, 40, 30];
assert!(v.ends_with(&[30]));
assert!(v.ends_with(&[40, 30]));
assert!(v.ends_with(&v));
assert!(!v.ends_with(&[50]));
assert!(!v.ends_with(&[50, 30]));
Always returns true if needle is an empty slice:
let v = &[10, 40, 30];
assert!(v.ends_with(&[]));
let v: &[u8] = &[];
assert!(v.ends_with(&[]));
1.51.0 · Source
Returns a subslice with the prefix removed.
If the slice starts with prefix, returns the subslice after the prefix, wrapped in Some.
If prefix is empty, simply returns the original slice. If prefix is equal to the
original slice, returns an empty slice.
If the slice does not start with prefix, returns None.
§ Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
assert_eq!(v.strip_prefix(&[10, 40, 30]), Some(&[][..]));
assert_eq!(v.strip_prefix(&[50]), None);
assert_eq!(v.strip_prefix(&[10, 50]), None);
let prefix : &str = "he";
assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
Some(b"llo".as_ref()));
1.51.0 · Source
Returns a subslice with the suffix removed.
If the slice ends with suffix, returns the subslice before the suffix, wrapped in Some.
If suffix is empty, simply returns the original slice. If suffix is equal to the
original slice, returns an empty slice.
If the slice does not end with suffix, returns None.
§ Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
assert_eq!(v.strip_suffix(&[10, 40, 30]), Some(&[][..]));
assert_eq!(v.strip_suffix(&[50]), None);
assert_eq!(v.strip_suffix(&[50, 30]), None);
1.0.0 · Source
Binary searches this slice for a given element. If the slice is not sorted, the returned result is unspecified and meaningless.
If the value is found then Result::Ok is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. The index is chosen
deterministically, but is subject to change in future versions of Rust.
If the value is not found then Result::Err is returned, containing
the index where a matching element could be inserted while maintaining
sorted order.
See also binary_search_by, binary_search_by_key, and partition_point.
§ Examples
Looks up a series of four elements. The first is found, with a
uniquely determined position; the second and third are not
found; the fourth could match any position in [1, 4].
let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
assert_eq!(s.binary_search(&13), Ok(9));
assert_eq!(s.binary_search(&4), Err(7));
assert_eq!(s.binary_search(&100), Err(13));
let r = s.binary_search(&1);
assert!(match r { Ok(1..=4) => true, _ => false, });
If you want to find that whole range of matching items, rather than
an arbitrary matching one, that can be done using partition_point:
let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let low = s.partition_point(|x| x < &1);
assert_eq!(low, 1);
let high = s.partition_point(|x| x <= &1);
assert_eq!(high, 5);
let r = s.binary_search(&1);
assert!((low..high).contains(&r.unwrap()));
assert!(s[..low].iter().all(|&x| x < 1));
assert!(s[low..high].iter().all(|&x| x == 1));
assert!(s[high..].iter().all(|&x| x > 1));
// For something not found, the "range" of equal items is empty
assert_eq!(s.partition_point(|x| x < &11), 9);
assert_eq!(s.partition_point(|x| x <= &11), 9);
assert_eq!(s.binary_search(&11), Err(9));
If you want to insert an item to a sorted vector, while maintaining
sort order, consider using partition_point:
let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x <= num);
// If `num` is unique, `s.partition_point(|&x| x < num)` (with `<`) is equivalent to
// `s.binary_search(&num).unwrap_or_else(|x| x)`, but using `<=` will allow `insert`
// to shift less elements.
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
1.0.0 · Source
Binary searches this slice with a comparator function.
The comparator function should return an order code that indicates
whether its argument is Less, Equal or Greater the desired
target.
If the slice is not sorted or if the comparator function does not
implement an order consistent with the sort order of the underlying
slice, the returned result is unspecified and meaningless.
If the value is found then Result::Ok is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. The index is chosen
deterministically, but is subject to change in future versions of Rust.
If the value is not found then Result::Err is returned, containing
the index where a matching element could be inserted while maintaining
sorted order.
See also binary_search, binary_search_by_key, and partition_point.
§ Examples
Looks up a series of four elements. The first is found, with a
uniquely determined position; the second and third are not
found; the fourth could match any position in [1, 4].
let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let seek = 13;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
let seek = 4;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
let seek = 100;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
let seek = 1;
let r = s.binary_search_by(|probe| probe.cmp(&seek));
assert!(match r { Ok(1..=4) => true, _ => false, });
1.10.0 · Source
Binary searches this slice with a key extraction function.
Assumes that the slice is sorted by the key, for instance with
sort_by_key using the same key extraction function.
If the slice is not sorted by the key, the returned result is
unspecified and meaningless.
If the value is found then Result::Ok is returned, containing the
index of the matching element. If there are multiple matches, then any
one of the matches could be returned. The index is chosen
deterministically, but is subject to change in future versions of Rust.
If the value is not found then Result::Err is returned, containing
the index where a matching element could be inserted while maintaining
sorted order.
See also binary_search, binary_search_by, and partition_point.
§ Examples
Looks up a series of four elements in a slice of pairs sorted by
their second elements. The first is found, with a uniquely
determined position; the second and third are not found; the
fourth could match any position in [1, 4].
let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
(1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
(1, 21), (2, 34), (4, 55)];
assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b), Ok(9));
assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b), Err(7));
assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
let r = s.binary_search_by_key(&1, |&(a, b)| b);
assert!(match r { Ok(1..=4) => true, _ => false, });
1.20.0 · Source
Sorts the slice without preserving the initial order of equal elements.
This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O( n \* log( n)) worst-case.
If the implementation of Ord for T does not implement a total order the resulting
order of elements in the slice is unspecified. All original elements will remain in the
slice and any possible modifications via interior mutability are observed in the input. Same
is true if the implementation of Ord for T panics.
Sorting types that only implement PartialOrd such as f32 and f64 require
additional precautions. For example, f32::NAN != f32::NAN, which doesn’t fulfill the
reflexivity requirement of Ord. By using an alternative comparison function with
slice::sort_unstable_by such as f32::total_cmp or f64::total_cmp that defines a
total order users can sort slices containing floating-point values. Alternatively, if all
values in the slice are guaranteed to be in a subset for which PartialOrd::partial_cmp
forms a total order, it’s possible to sort the slice with sort_unstable_by(|a, b| a.partial_cmp(b).unwrap()).
§ Current implementation
The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.
§ Panics
May panic if the implementation of Ord for T does not implement a total order.
§ Examples
let mut v = [4, -5, 1, -3, 2];
v.sort_unstable();
assert_eq!(v, [-5, -3, 1, 2, 4]);
1.20.0 · Source
Sorts the slice with a comparison function, without preserving the initial order of equal elements.
This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O( n \* log( n)) worst-case.
If the comparison function compare does not implement a total order the resulting order
of elements in the slice is unspecified. All original elements will remain in the slice and
any possible modifications via interior mutability are observed in the input. Same is true
if compare panics.
For example |a, b| (a - b).cmp(a) is a comparison function that is neither transitive nor
reflexive nor total, a < b < c < a with a = 1, b = 2, c = 3. For more information and
examples see the Ord documentation.
§ Current implementation
The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.
§ Panics
May panic if compare does not implement a total order.
§ Examples
let mut v = [4, -5, 1, -3, 2];
v.sort_unstable_by(|a, b| a.cmp(b));
assert_eq!(v, [-5, -3, 1, 2, 4]);
// reverse sorting
v.sort_unstable_by(|a, b| b.cmp(a));
assert_eq!(v, [4, 2, 1, -3, -5]);
1.20.0 · Source
Sorts the slice with a key extraction function, without preserving the initial order of equal elements.
This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O( n \* log( n)) worst-case.
If the implementation of Ord for K does not implement a total order the resulting
order of elements in the slice is unspecified. All original elements will remain in the
slice and any possible modifications via interior mutability are observed in the input. Same
is true if the implementation of Ord for K panics.
§ Current implementation
The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.
§ Panics
May panic if the implementation of Ord for K does not implement a total order.
§ Examples
let mut v = [4i32, -5, 1, -3, 2];
v.sort_unstable_by_key(|k| k.abs());
assert_eq!(v, [1, 2, -3, 4, -5]);
1.49.0 · Source
Reorders the slice such that the element at index is at a sort-order position. All
elements before index will be <= to this value, and all elements after will be >= to
it.
This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O( n) time. This function is also known as “kth element” in other libraries.
Returns a triple that partitions the reordered slice:
The unsorted subslice before
index, whose elements all satisfyx <= self[index].The element at
index.The unsorted subslice after
index, whose elements all satisfyx >= self[index].
§ Current implementation
The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll
and Orson Peters, which is also the basis for sort_unstable. The fallback algorithm is
Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime
for all inputs.
§ Panics
Panics when index >= len(), and so always panics on empty slices.
May panic if the implementation of Ord for T does not implement a total order.
§ Examples
let mut v = [-5i32, 4, 2, -3, 1];
// Find the items `<=` to the median, the median itself, and the items `>=` to it.
let (lesser, median, greater) = v.select_nth_unstable(2);
assert!(lesser == [-3, -5] || lesser == [-5, -3]);
assert_eq!(median, &mut 1);
assert!(greater == [4, 2] || greater == [2, 4]);
// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [-3, -5, 1, 2, 4] ||
v == [-5, -3, 1, 2, 4] ||
v == [-3, -5, 1, 4, 2] ||
v == [-5, -3, 1, 4, 2]);
1.49.0 · Source
Reorders the slice with a comparator function such that the element at index is at a
sort-order position. All elements before index will be <= to this value, and all
elements after will be >= to it, according to the comparator function.
This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O( n) time. This function is also known as “kth element” in other libraries.
Returns a triple partitioning the reordered slice:
The unsorted subslice before
index, whose elements all satisfycompare(x, self[index]).is_le().The element at
index.The unsorted subslice after
index, whose elements all satisfycompare(x, self[index]).is_ge().
§ Current implementation
The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll
and Orson Peters, which is also the basis for sort_unstable. The fallback algorithm is
Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime
for all inputs.
§ Panics
Panics when index >= len(), and so always panics on empty slices.
May panic if compare does not implement a total order.
§ Examples
let mut v = [-5i32, 4, 2, -3, 1];
// Find the items `>=` to the median, the median itself, and the items `<=` to it, by using
// a reversed comparator.
let (before, median, after) = v.select_nth_unstable_by(2, |a, b| b.cmp(a));
assert!(before == [4, 2] || before == [2, 4]);
assert_eq!(median, &mut 1);
assert!(after == [-3, -5] || after == [-5, -3]);
// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [2, 4, 1, -5, -3] ||
v == [2, 4, 1, -3, -5] ||
v == [4, 2, 1, -5, -3] ||
v == [4, 2, 1, -3, -5]);
1.49.0 · Source
Reorders the slice with a key extraction function such that the element at index is at a
sort-order position. All elements before index will have keys <= to the key at index,
and all elements after will have keys >= to it.
This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O( n) time. This function is also known as “kth element” in other libraries.
Returns a triple partitioning the reordered slice:
The unsorted subslice before
index, whose elements all satisfyf(x) <= f(self[index]).The element at
index.The unsorted subslice after
index, whose elements all satisfyf(x) >= f(self[index]).
§ Current implementation
The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll
and Orson Peters, which is also the basis for sort_unstable. The fallback algorithm is
Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime
for all inputs.
§ Panics
Panics when index >= len(), meaning it always panics on empty slices.
May panic if K: Ord does not implement a total order.
§ Examples
let mut v = [-5i32, 4, 1, -3, 2];
// Find the items `<=` to the absolute median, the absolute median itself, and the items
// `>=` to it.
let (lesser, median, greater) = v.select_nth_unstable_by_key(2, |a| a.abs());
assert!(lesser == [1, 2] || lesser == [2, 1]);
assert_eq!(median, &mut -3);
assert!(greater == [4, -5] || greater == [-5, 4]);
// We are only guaranteed the slice will be one of the following, based on the way we sort
// about the specified index.
assert!(v == [1, 2, -3, 4, -5] ||
v == [1, 2, -3, -5, 4] ||
v == [2, 1, -3, 4, -5] ||
v == [2, 1, -3, -5, 4]);
Source
🔬This is a nightly-only experimental API. ( slice_partition_dedup #54279)
Moves all consecutive repeated elements to the end of the slice according to the
PartialEq trait implementation.
Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.
If the slice is sorted, the first returned slice contains no duplicates.
§ Examples
#![feature(slice_partition_dedup)]
let mut slice = [1, 2, 2, 3, 3, 2, 1, 1];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, [1, 2, 3, 2, 1]);
assert_eq!(duplicates, [2, 3, 1]);
Source
🔬This is a nightly-only experimental API. ( slice_partition_dedup #54279)
Moves all but the first of consecutive elements to the end of the slice satisfying a given equality relation.
Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.
The same_bucket function is passed references to two elements from the slice and
must determine if the elements compare equal. The elements are passed in opposite order
from their order in the slice, so if same_bucket(a, b) returns true, a is moved
at the end of the slice.
If the slice is sorted, the first returned slice contains no duplicates.
§ Examples
#![feature(slice_partition_dedup)]
let mut slice = ["foo", "Foo", "BAZ", "Bar", "bar", "baz", "BAZ"];
let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.eq_ignore_ascii_case(b));
assert_eq!(dedup, ["foo", "BAZ", "Bar", "baz"]);
assert_eq!(duplicates, ["bar", "Foo", "BAZ"]);
Source
🔬This is a nightly-only experimental API. ( slice_partition_dedup #54279)
Moves all but the first of consecutive elements to the end of the slice that resolve to the same key.
Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.
If the slice is sorted, the first returned slice contains no duplicates.
§ Examples
#![feature(slice_partition_dedup)]
let mut slice = [10, 20, 21, 30, 30, 20, 11, 13];
let (dedup, duplicates) = slice.partition_dedup_by_key(|i| *i / 10);
assert_eq!(dedup, [10, 20, 30, 20, 11]);
assert_eq!(duplicates, [21, 30, 13]);
1.26.0 · Source
Rotates the slice in-place such that the first mid elements of the
slice move to the end while the last self.len() - mid elements move to
the front.
After calling rotate_left, the element previously at index mid will
become the first element in the slice.
§ Panics
This function will panic if mid is greater than the length of the
slice. Note that mid == self.len() does not panic and is a no-op
rotation.
§ Complexity
Takes linear (in self.len()) time.
§ Examples
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_left(2);
assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);
Rotating a subslice:
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_left(1);
assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);
1.26.0 · Source
Rotates the slice in-place such that the first self.len() - k
elements of the slice move to the end while the last k elements move
to the front.
After calling rotate_right, the element previously at index
self.len() - k will become the first element in the slice.
§ Panics
This function will panic if k is greater than the length of the
slice. Note that k == self.len() does not panic and is a no-op
rotation.
§ Complexity
Takes linear (in self.len()) time.
§ Examples
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_right(2);
assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);
Rotating a subslice:
let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_right(1);
assert_eq!(a, ['a', 'e', 'b', 'c', 'd', 'f']);
1.50.0 · Source
Fills self with elements by cloning value.
§ Examples
let mut buf = vec![0; 10];
buf.fill(1);
assert_eq!(buf, vec![1; 10]);
1.51.0 · Source
Fills self with elements returned by calling a closure repeatedly.
This method uses a closure to create new values. If you’d rather
Clone a given value, use fill. If you want to use the Default
trait to generate values, you can pass Default::default as the
argument.
§ Examples
let mut buf = vec![1; 10];
buf.fill_with(Default::default);
assert_eq!(buf, vec![0; 10]);
1.7.0 · Source
Copies the elements from src into self.
The length of src must be the same as self.
§ Panics
This function will panic if the two slices have different lengths.
§ Examples
Cloning two elements from a slice into another:
let src = [1, 2, 3, 4];
let mut dst = [0, 0];
// Because the slices have to be the same length,
// we slice the source slice from four elements
// to two. It will panic if we don't do this.
dst.clone_from_slice(&src[2..]);
assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);
Rust enforces that there can only be one mutable reference with no
immutable references to a particular piece of data in a particular
scope. Because of this, attempting to use clone_from_slice on a
single slice will result in a compile failure:
ⓘ
let mut slice = [1, 2, 3, 4, 5];
slice[..2].clone_from_slice(&slice[3..]); // compile fail!
To work around this, we can use split_at_mut to create two distinct
sub-slices from a slice:
let mut slice = [1, 2, 3, 4, 5];
{
let (left, right) = slice.split_at_mut(2);
left.clone_from_slice(&right[1..]);
}
assert_eq!(slice, [4, 5, 3, 4, 5]);
1.9.0 (const: unstable) · Source
Copies all elements from src into self, using a memcpy.
The length of src must be the same as self.
If T does not implement Copy, use clone_from_slice.
§ Panics
This function will panic if the two slices have different lengths.
§ Examples
Copying two elements from a slice into another:
let src = [1, 2, 3, 4];
let mut dst = [0, 0];
// Because the slices have to be the same length,
// we slice the source slice from four elements
// to two. It will panic if we don't do this.
dst.copy_from_slice(&src[2..]);
assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);
Rust enforces that there can only be one mutable reference with no
immutable references to a particular piece of data in a particular
scope. Because of this, attempting to use copy_from_slice on a
single slice will result in a compile failure:
ⓘ
let mut slice = [1, 2, 3, 4, 5];
slice[..2].copy_from_slice(&slice[3..]); // compile fail!
To work around this, we can use split_at_mut to create two distinct
sub-slices from a slice:
let mut slice = [1, 2, 3, 4, 5];
{
let (left, right) = slice.split_at_mut(2);
left.copy_from_slice(&right[1..]);
}
assert_eq!(slice, [4, 5, 3, 4, 5]);
1.37.0 · Source
Copies elements from one part of the slice to another part of itself, using a memmove.
src is the range within self to copy from. dest is the starting
index of the range within self to copy to, which will have the same
length as src. The two ranges may overlap. The ends of the two ranges
must be less than or equal to self.len().
§ Panics
This function will panic if either range exceeds the end of the slice,
or if the end of src is before the start.
§ Examples
Copying four bytes within a slice:
let mut bytes = *b"Hello, World!";
bytes.copy_within(1..5, 8);
assert_eq!(&bytes, b"Hello, Wello!");
1.27.0 · Source
Swaps all elements in self with those in other.
The length of other must be the same as self.
§ Panics
This function will panic if the two slices have different lengths.
§ Example
Swapping two elements across slices:
let mut slice1 = [0, 0];
let mut slice2 = [1, 2, 3, 4];
slice1.swap_with_slice(&mut slice2[2..]);
assert_eq!(slice1, [3, 4]);
assert_eq!(slice2, [1, 2, 0, 0]);
Rust enforces that there can only be one mutable reference to a
particular piece of data in a particular scope. Because of this,
attempting to use swap_with_slice on a single slice will result in
a compile failure:
ⓘ
let mut slice = [1, 2, 3, 4, 5];
slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!
To work around this, we can use split_at_mut to create two distinct
mutable sub-slices from a slice:
let mut slice = [1, 2, 3, 4, 5];
{
let (left, right) = slice.split_at_mut(2);
left.swap_with_slice(&mut right[1..]);
}
assert_eq!(slice, [4, 5, 3, 1, 2]);
1.30.0 · Source
Transmutes the slice to a slice of another type, ensuring alignment of the types is maintained.
This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The middle part will be as big as possible under the given alignment constraint and element size.
This method has no purpose when either input element T or output element U are
zero-sized and will return the original slice without splitting anything.
§ Safety
This method is essentially a transmute with respect to the elements in the returned
middle slice, so all the usual caveats pertaining to transmute::<T, U> also apply here.
§ Examples
Basic usage:
unsafe {
let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
let (prefix, shorts, suffix) = bytes.align_to::<u16>();
// less_efficient_algorithm_for_bytes(prefix);
// more_efficient_algorithm_for_aligned_shorts(shorts);
// less_efficient_algorithm_for_bytes(suffix);
}
1.30.0 · Source
Transmutes the mutable slice to a mutable slice of another type, ensuring alignment of the types is maintained.
This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The middle part will be as big as possible under the given alignment constraint and element size.
This method has no purpose when either input element T or output element U are
zero-sized and will return the original slice without splitting anything.
§ Safety
This method is essentially a transmute with respect to the elements in the returned
middle slice, so all the usual caveats pertaining to transmute::<T, U> also apply here.
§ Examples
Basic usage:
unsafe {
let mut bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
let (prefix, shorts, suffix) = bytes.align_to_mut::<u16>();
// less_efficient_algorithm_for_bytes(prefix);
// more_efficient_algorithm_for_aligned_shorts(shorts);
// less_efficient_algorithm_for_bytes(suffix);
}
Source
🔬This is a nightly-only experimental API. ( portable_simd #86656)
Splits a slice into a prefix, a middle of aligned SIMD types, and a suffix.
This is a safe wrapper around slice::align_to, so inherits the same
guarantees as that method.
§ Panics
This will panic if the size of the SIMD type is different from
LANES times that of the scalar.
At the time of writing, the trait restrictions on Simd<T, LANES> keeps
that from ever happening, as only power-of-two numbers of lanes are
supported. It’s possible that, in the future, those restrictions might
be lifted in a way that would make it possible to see panics from this
method for something like LANES == 3.
§ Examples
#![feature(portable_simd)]
use core::simd::prelude::*;
let short = &[1, 2, 3];
let (prefix, middle, suffix) = short.as_simd::<4>();
assert_eq!(middle, []); // Not enough elements for anything in the middle
// They might be split in any possible way between prefix and suffix
let it = prefix.iter().chain(suffix).copied();
assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);
fn basic_simd_sum(x: &[f32]) -> f32 {
use std::ops::Add;
let (prefix, middle, suffix) = x.as_simd();
let sums = f32x4::from_array([
prefix.iter().copied().sum(),
0.0,
0.0,
suffix.iter().copied().sum(),
]);
let sums = middle.iter().copied().fold(sums, f32x4::add);
sums.reduce_sum()
}
let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);
Source
🔬This is a nightly-only experimental API. ( portable_simd #86656)
Splits a mutable slice into a mutable prefix, a middle of aligned SIMD types, and a mutable suffix.
This is a safe wrapper around slice::align_to_mut, so inherits the same
guarantees as that method.
This is the mutable version of slice::as_simd; see that for examples.
§ Panics
This will panic if the size of the SIMD type is different from
LANES times that of the scalar.
At the time of writing, the trait restrictions on Simd<T, LANES> keeps
that from ever happening, as only power-of-two numbers of lanes are
supported. It’s possible that, in the future, those restrictions might
be lifted in a way that would make it possible to see panics from this
method for something like LANES == 3.
1.82.0 · Source
Checks if the elements of this slice are sorted.
That is, for each element a and its following element b, a <= b must hold. If the
slice yields exactly zero or one element, true is returned.
Note that if Self::Item is only PartialOrd, but not Ord, the above definition
implies that this function returns false if any two consecutive items are not
comparable.
§ Examples
let empty: [i32; 0] = [];
assert!([1, 2, 2, 9].is_sorted());
assert!(![1, 3, 2, 4].is_sorted());
assert!([0].is_sorted());
assert!(empty.is_sorted());
assert!(![0.0, 1.0, f32::NAN].is_sorted());
1.82.0 · Source
Checks if the elements of this slice are sorted using the given comparator function.
Instead of using PartialOrd::partial_cmp, this function uses the given compare
function to determine whether two elements are to be considered in sorted order.
§ Examples
assert!([1, 2, 2, 9].is_sorted_by(|a, b| a <= b));
assert!(![1, 2, 2, 9].is_sorted_by(|a, b| a < b));
assert!([0].is_sorted_by(|a, b| true));
assert!([0].is_sorted_by(|a, b| false));
let empty: [i32; 0] = [];
assert!(empty.is_sorted_by(|a, b| false));
assert!(empty.is_sorted_by(|a, b| true));
1.82.0 · Source
Checks if the elements of this slice are sorted using the given key extraction function.
Instead of comparing the slice’s elements directly, this function compares the keys of the
elements, as determined by f. Apart from that, it’s equivalent to is_sorted; see its
documentation for more information.
§ Examples
assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
1.52.0 · Source
Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).
The slice is assumed to be partitioned according to the given predicate.
This means that all elements for which the predicate returns true are at the start of the slice
and all elements for which the predicate returns false are at the end.
For example, [7, 15, 3, 5, 4, 12, 6] is partitioned under the predicate x % 2 != 0
(all odd numbers are at the start, all even at the end).
If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.
See also binary_search, binary_search_by, and binary_search_by_key.
§ Examples
let v = [1, 2, 3, 3, 5, 6, 7];
let i = v.partition_point(|&x| x < 5);
assert_eq!(i, 4);
assert!(v[..i].iter().all(|&x| x < 5));
assert!(v[i..].iter().all(|&x| !(x < 5)));
If all elements of the slice match the predicate, including if the slice is empty, then the length of the slice will be returned:
let a = [2, 4, 8];
assert_eq!(a.partition_point(|x| x < &100), a.len());
let a: [i32; 0] = [];
assert_eq!(a.partition_point(|x| x < &100), 0);
If you want to insert an item to a sorted vector, while maintaining sort order:
let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x <= num);
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the subslice corresponding to the given range and returns a reference to it.
Returns None and does not modify the slice if the given
range is out of bounds.
Note that this method only accepts one-sided ranges such as
2.. or ..6, but not 2..6.
§ Examples
Splitting off the first three elements of a slice:
#![feature(slice_take)]
let mut slice: &[_] = &['a', 'b', 'c', 'd'];
let mut first_three = slice.split_off(..3).unwrap();
assert_eq!(slice, &['d']);
assert_eq!(first_three, &['a', 'b', 'c']);
Splitting off the last two elements of a slice:
#![feature(slice_take)]
let mut slice: &[_] = &['a', 'b', 'c', 'd'];
let mut tail = slice.split_off(2..).unwrap();
assert_eq!(slice, &['a', 'b']);
assert_eq!(tail, &['c', 'd']);
Getting None when range is out of bounds:
#![feature(slice_take)]
let mut slice: &[_] = &['a', 'b', 'c', 'd'];
assert_eq!(None, slice.split_off(5..));
assert_eq!(None, slice.split_off(..5));
assert_eq!(None, slice.split_off(..=4));
let expected: &[char] = &['a', 'b', 'c', 'd'];
assert_eq!(Some(expected), slice.split_off(..4));
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the subslice corresponding to the given range and returns a mutable reference to it.
Returns None and does not modify the slice if the given
range is out of bounds.
Note that this method only accepts one-sided ranges such as
2.. or ..6, but not 2..6.
§ Examples
Splitting off the first three elements of a slice:
#![feature(slice_take)]
let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
let mut first_three = slice.split_off_mut(..3).unwrap();
assert_eq!(slice, &mut ['d']);
assert_eq!(first_three, &mut ['a', 'b', 'c']);
Taking the last two elements of a slice:
#![feature(slice_take)]
let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
let mut tail = slice.split_off_mut(2..).unwrap();
assert_eq!(slice, &mut ['a', 'b']);
assert_eq!(tail, &mut ['c', 'd']);
Getting None when range is out of bounds:
#![feature(slice_take)]
let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
assert_eq!(None, slice.split_off_mut(5..));
assert_eq!(None, slice.split_off_mut(..5));
assert_eq!(None, slice.split_off_mut(..=4));
let expected: &mut [_] = &mut ['a', 'b', 'c', 'd'];
assert_eq!(Some(expected), slice.split_off_mut(..4));
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the first element of the slice and returns a reference to it.
Returns None if the slice is empty.
§ Examples
#![feature(slice_take)]
let mut slice: &[_] = &['a', 'b', 'c'];
let first = slice.split_off_first().unwrap();
assert_eq!(slice, &['b', 'c']);
assert_eq!(first, &'a');
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the first element of the slice and returns a mutable reference to it.
Returns None if the slice is empty.
§ Examples
#![feature(slice_take)]
let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
let first = slice.split_off_first_mut().unwrap();
*first = 'd';
assert_eq!(slice, &['b', 'c']);
assert_eq!(first, &'d');
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the last element of the slice and returns a reference to it.
Returns None if the slice is empty.
§ Examples
#![feature(slice_take)]
let mut slice: &[_] = &['a', 'b', 'c'];
let last = slice.split_off_last().unwrap();
assert_eq!(slice, &['a', 'b']);
assert_eq!(last, &'c');
Source
🔬This is a nightly-only experimental API. ( slice_take #62280)
Removes the last element of the slice and returns a mutable reference to it.
Returns None if the slice is empty.
§ Examples
#![feature(slice_take)]
let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
let last = slice.split_off_last_mut().unwrap();
*last = 'd';
assert_eq!(slice, &['a', 'b']);
assert_eq!(last, &'d');
1.86.0 · Source
Returns mutable references to many indices at once, without doing any checks.
An index can be either a usize, a Range or a RangeInclusive. Note
that this method takes an array, so all indices must be of the same type.
If passed an array of usize s this method gives back an array of mutable references
to single elements, while if passed an array of ranges it gives back an array of
mutable references to slices.
For a safe alternative see get_disjoint_mut.
§ Safety
Calling this method with overlapping or out-of-bounds indices is undefined behavior even if the resulting references are not used.
§ Examples
let x = &mut [1, 2, 4];
unsafe {
let [a, b] = x.get_disjoint_unchecked_mut([0, 2]);
*a *= 10;
*b *= 100;
}
assert_eq!(x, &[10, 2, 400]);
unsafe {
let [a, b] = x.get_disjoint_unchecked_mut([0..1, 1..3]);
a[0] = 8;
b[0] = 88;
b[1] = 888;
}
assert_eq!(x, &[8, 88, 888]);
unsafe {
let [a, b] = x.get_disjoint_unchecked_mut([1..=2, 0..=0]);
a[0] = 11;
a[1] = 111;
b[0] = 1;
}
assert_eq!(x, &[1, 11, 111]);
1.86.0 · Source
Returns mutable references to many indices at once.
An index can be either a usize, a Range or a RangeInclusive. Note
that this method takes an array, so all indices must be of the same type.
If passed an array of usize s this method gives back an array of mutable references
to single elements, while if passed an array of ranges it gives back an array of
mutable references to slices.
Returns an error if any index is out-of-bounds, or if there are overlapping indices. An empty range is not considered to overlap if it is located at the beginning or at the end of another range, but is considered to overlap if it is located in the middle.
This method does a O(n^2) check to check that there are no overlapping indices, so be careful when passing many indices.
§ Examples
let v = &mut [1, 2, 3];
if let Ok([a, b]) = v.get_disjoint_mut([0, 2]) {
*a = 413;
*b = 612;
}
assert_eq!(v, &[413, 2, 612]);
if let Ok([a, b]) = v.get_disjoint_mut([0..1, 1..3]) {
a[0] = 8;
b[0] = 88;
b[1] = 888;
}
assert_eq!(v, &[8, 88, 888]);
if let Ok([a, b]) = v.get_disjoint_mut([1..=2, 0..=0]) {
a[0] = 11;
a[1] = 111;
b[0] = 1;
}
assert_eq!(v, &[1, 11, 111]);
Source
🔬This is a nightly-only experimental API. ( substr_range #126769)
Returns the index that an element reference points to.
Returns None if element does not point to the start of an element within the slice.
This method is useful for extending slice iterators like slice::split.
Note that this uses pointer arithmetic and does not compare elements.
To find the index of an element via comparison, use
.iter().position() instead.
§ Panics
Panics if T is zero-sized.
§ Examples
Basic usage:
#![feature(substr_range)]
let nums: &[u32] = &[1, 7, 1, 1];
let num = &nums[2];
assert_eq!(num, &1);
assert_eq!(nums.element_offset(num), Some(2));
Returning None with an unaligned element:
#![feature(substr_range)]
let arr: &[[u32; 2]] = &[[0, 1], [2, 3]];
let flat_arr: &[u32] = arr.as_flattened();
let ok_elm: &[u32; 2] = flat_arr[0..2].try_into().unwrap();
let weird_elm: &[u32; 2] = flat_arr[1..3].try_into().unwrap();
assert_eq!(ok_elm, &[0, 1]);
assert_eq!(weird_elm, &[1, 2]);
assert_eq!(arr.element_offset(ok_elm), Some(0)); // Points to element 0
assert_eq!(arr.element_offset(weird_elm), None); // Points between element 0 and 1
Source
🔬This is a nightly-only experimental API. ( substr_range #126769)
Returns the range of indices that a subslice points to.
Returns None if subslice does not point within the slice or if it is not aligned with the
elements in the slice.
This method does not compare elements. Instead, this method finds the location in the slice that
subslice was obtained from. To find the index of a subslice via comparison, instead use
.windows() .position().
This method is useful for extending slice iterators like slice::split.
Note that this may return a false positive (either Some(0..0) or Some(self.len()..self.len()))
if subslice has a length of zero and points to the beginning or end of another, separate, slice.
§ Panics
Panics if T is zero-sized.
§ Examples
Basic usage:
#![feature(substr_range)]
let nums = &[0, 5, 10, 0, 0, 5];
let mut iter = nums
.split(|t| *t == 0)
.map(|n| nums.subslice_range(n).unwrap());
assert_eq!(iter.next(), Some(0..0));
assert_eq!(iter.next(), Some(1..3));
assert_eq!(iter.next(), Some(4..4));
assert_eq!(iter.next(), Some(5..6));
1.80.0 (const: unstable) · Source
Takes a &[[T; N]], and flattens it to a &[T].
§ Panics
This panics if the length of the resulting slice would overflow a usize.
This is only possible when flattening a slice of arrays of zero-sized
types, and thus tends to be irrelevant in practice. If
size_of::<T>() > 0, this will never panic.
§ Examples
assert_eq!([[1, 2, 3], [4, 5, 6]].as_flattened(), &[1, 2, 3, 4, 5, 6]);
assert_eq!(
[[1, 2, 3], [4, 5, 6]].as_flattened(),
[[1, 2], [3, 4], [5, 6]].as_flattened(),
);
let slice_of_empty_arrays: &[[i32; 0]] = &[[], [], [], [], []];
assert!(slice_of_empty_arrays.as_flattened().is_empty());
let empty_slice_of_arrays: &[[u32; 10]] = &[];
assert!(empty_slice_of_arrays.as_flattened().is_empty());
1.80.0 (const: unstable) · Source
Takes a &mut [[T; N]], and flattens it to a &mut [T].
§ Panics
This panics if the length of the resulting slice would overflow a usize.
This is only possible when flattening a slice of arrays of zero-sized
types, and thus tends to be irrelevant in practice. If
size_of::<T>() > 0, this will never panic.
§ Examples
fn add_5_to_all(slice: &mut [i32]) {
for i in slice {
*i += 5;
}
}
let mut array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
add_5_to_all(array.as_flattened_mut());
assert_eq!(array, [[6, 7, 8], [9, 10, 11], [12, 13, 14]]);
Source
🔬This is a nightly-only experimental API. ( sort_floats #93396)
Sorts the slice of floats.
This sort is in-place (i.e. does not allocate), O( n \* log( n)) worst-case, and uses
the ordering defined by f32::total_cmp.
§ Current implementation
This uses the same sorting algorithm as sort_unstable_by.
§ Examples
#![feature(sort_floats)]
let mut v = [2.6, -5e-8, f32::NAN, 8.29, f32::INFINITY, -1.0, 0.0, -f32::INFINITY, -0.0];
v.sort_floats();
let sorted = [-f32::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f32::INFINITY, f32::NAN];
assert_eq!(&v[..8], &sorted[..8]);
assert!(v[8].is_nan());
Source
🔬This is a nightly-only experimental API. ( sort_floats #93396)
Sorts the slice of floats.
This sort is in-place (i.e. does not allocate), O( n \* log( n)) worst-case, and uses
the ordering defined by f64::total_cmp.
§ Current implementation
This uses the same sorting algorithm as sort_unstable_by.
§ Examples
#![feature(sort_floats)]
let mut v = [2.6, -5e-8, f64::NAN, 8.29, f64::INFINITY, -1.0, 0.0, -f64::INFINITY, -0.0];
v.sort_floats();
let sorted = [-f64::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f64::INFINITY, f64::NAN];
assert_eq!(&v[..8], &sorted[..8]);
assert!(v[8].is_nan());
1.79.0 · Source
Creates an iterator over the contiguous valid UTF-8 ranges of this slice, and the non-UTF-8 fragments in between.
See the Utf8Chunk type for documentation of the items yielded by this iterator.
§ Examples
This function formats arbitrary but mostly-UTF-8 bytes into Rust source
code in the form of a C-string literal ( c"...").
use std::fmt::Write as _;
pub fn cstr_literal(bytes: &[u8]) -> String {
let mut repr = String::new();
repr.push_str("c\"");
for chunk in bytes.utf8_chunks() {
for ch in chunk.valid().chars() {
// Escapes \0, \t, \r, \n, \\, \', \", and uses \u{...} for non-printable characters.
write!(repr, "{}", ch.escape_debug()).unwrap();
}
for byte in chunk.invalid() {
write!(repr, "\\x{:02X}", byte).unwrap();
}
}
repr.push('"');
repr
}
fn main() {
let lit = cstr_literal(b"\xferris the \xf0\x9f\xa6\x80\x07");
let expected = stringify!(c"\xFErris the 🦀\u{7}");
assert_eq!(lit, expected);
}
1.0.0 · Source
Sorts the slice, preserving initial order of equal elements.
This sort is stable (i.e., does not reorder equal elements) and O( n \* log( n)) worst-case.
If the implementation of Ord for T does not implement a total order, the function
may panic; even if the function exits normally, the resulting order of elements in the slice
is unspecified. See also the note on panicking below.
When applicable, unstable sorting is preferred because it is generally faster than stable
sorting and it doesn’t allocate auxiliary memory. See
sort_unstable. The exception are partially sorted slices, which
may be better served with slice::sort.
Sorting types that only implement PartialOrd such as f32 and f64 require
additional precautions. For example, f32::NAN != f32::NAN, which doesn’t fulfill the
reflexivity requirement of Ord. By using an alternative comparison function with
slice::sort_by such as f32::total_cmp or f64::total_cmp that defines a [total
order](https://en.wikipedia.org/wiki/Total_order) users can sort slices containing floating-point values. Alternatively, if all values
in the slice are guaranteed to be in a subset for which PartialOrd::partial_cmp forms a
total order, it’s possible to sort the slice with sort_by(|a, b| a.partial_cmp(b).unwrap()).
§ Current implementation
The current implementation is based on driftsort by Orson Peters and Lukas Bergdoll, which combines the fast average case of quicksort with the fast worst case and partial run detection of mergesort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
The auxiliary memory allocation behavior depends on the input length. Short slices are
handled without allocation, medium sized slices allocate self.len() and beyond that it
clamps at self.len() / 2.
§ Panics
May panic if the implementation of Ord for T does not implement a total order, or if
the Ord implementation itself panics.
All safe functions on slices preserve the invariant that even if the function panics, all
original elements will remain in the slice and any possible modifications via interior
mutability are observed in the input. This ensures that recovery code (for instance inside
of a Drop or following a catch_unwind) will still have access to all the original
elements. For instance, if the slice belongs to a Vec, the Vec::drop method will be able
to dispose of all contained elements.
§ Examples
let mut v = [4, -5, 1, -3, 2];
v.sort();
assert_eq!(v, [-5, -3, 1, 2, 4]);
1.0.0 · Source
Sorts the slice with a comparison function, preserving initial order of equal elements.
This sort is stable (i.e., does not reorder equal elements) and O( n \* log( n)) worst-case.
If the comparison function compare does not implement a total order, the function may
panic; even if the function exits normally, the resulting order of elements in the slice is
unspecified. See also the note on panicking below.
For example |a, b| (a - b).cmp(a) is a comparison function that is neither transitive nor
reflexive nor total, a < b < c < a with a = 1, b = 2, c = 3. For more information and
examples see the Ord documentation.
§ Current implementation
The current implementation is based on driftsort by Orson Peters and Lukas Bergdoll, which combines the fast average case of quicksort with the fast worst case and partial run detection of mergesort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
The auxiliary memory allocation behavior depends on the input length. Short slices are
handled without allocation, medium sized slices allocate self.len() and beyond that it
clamps at self.len() / 2.
§ Panics
May panic if compare does not implement a total order, or if compare itself panics.
All safe functions on slices preserve the invariant that even if the function panics, all
original elements will remain in the slice and any possible modifications via interior
mutability are observed in the input. This ensures that recovery code (for instance inside
of a Drop or following a catch_unwind) will still have access to all the original
elements. For instance, if the slice belongs to a Vec, the Vec::drop method will be able
to dispose of all contained elements.
§ Examples
let mut v = [4, -5, 1, -3, 2];
v.sort_by(|a, b| a.cmp(b));
assert_eq!(v, [-5, -3, 1, 2, 4]);
// reverse sorting
v.sort_by(|a, b| b.cmp(a));
assert_eq!(v, [4, 2, 1, -3, -5]);
1.7.0 · Source
Sorts the slice with a key extraction function, preserving initial order of equal elements.
This sort is stable (i.e., does not reorder equal elements) and O( m \* n \* log( n)) worst-case, where the key function is O( m).
If the implementation of Ord for K does not implement a total order, the function
may panic; even if the function exits normally, the resulting order of elements in the slice
is unspecified. See also the note on panicking below.
§ Current implementation
The current implementation is based on driftsort by Orson Peters and Lukas Bergdoll, which combines the fast average case of quicksort with the fast worst case and partial run detection of mergesort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O( n \* log( k)).
The auxiliary memory allocation behavior depends on the input length. Short slices are
handled without allocation, medium sized slices allocate self.len() and beyond that it
clamps at self.len() / 2.
§ Panics
May panic if the implementation of Ord for K does not implement a total order, or if
the Ord implementation or the key-function f panics.
All safe functions on slices preserve the invariant that even if the function panics, all
original elements will remain in the slice and any possible modifications via interior
mutability are observed in the input. This ensures that recovery code (for instance inside
of a Drop or following a catch_unwind) will still have access to all the original
elements. For instance, if the slice belongs to a Vec, the Vec::drop method will be able
to dispose of all contained elements.
§ Examples
let mut v = [4i32, -5, 1, -3, 2];
v.sort_by_key(|k| k.abs());
assert_eq!(v, [1, 2, -3, 4, -5]);
1.34.0 · Source
Sorts the slice with a key extraction function, preserving initial order of equal elements.
This sort is stable (i.e., does not reorder equal elements) and O( m \* n + n * log( n)) worst-case, where the key function is O( m).
During sorting, the key function is called at most once per element, by using temporary storage to remember the results of key evaluation. The order of calls to the key function is unspecified and may change in future versions of the standard library.
If the implementation of Ord for K does not implement a total order, the function
may panic; even if the function exits normally, the resulting order of elements in the slice
is unspecified. See also the note on panicking below.
For simple key functions (e.g., functions that are property accesses or basic operations),
sort_by_key is likely to be faster.
§ Current implementation
The current implementation is based on instruction-parallel-network sort by Lukas Bergdoll, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on fully sorted and reversed inputs. And O( k \* log( n)) where k is the number of distinct elements in the input. It leverages superscalar out-of-order execution capabilities commonly found in CPUs, to efficiently perform the operation.
In the worst case, the algorithm allocates temporary storage in a Vec<(K, usize)> the
length of the slice.
§ Panics
May panic if the implementation of Ord for K does not implement a total order, or if
the Ord implementation panics.
All safe functions on slices preserve the invariant that even if the function panics, all
original elements will remain in the slice and any possible modifications via interior
mutability are observed in the input. This ensures that recovery code (for instance inside
of a Drop or following a catch_unwind) will still have access to all the original
elements. For instance, if the slice belongs to a Vec, the Vec::drop method will be able
to dispose of all contained elements.
§ Examples
let mut v = [4i32, -5, 1, -3, 2, 10];
// Strings are sorted by lexicographical order.
v.sort_by_cached_key(|k| k.to_string());
assert_eq!(v, [-3, -5, 1, 10, 2, 4]);
1.0.0 · Source
Copies self into a new Vec.
§ Examples
let s = [10, 40, 30];
let x = s.to_vec();
// Here, `s` and `x` can be modified independently.
Source
🔬This is a nightly-only experimental API. ( allocator_api #32838)
Copies self into a new Vec with an allocator.
§ Examples
#![feature(allocator_api)]
use std::alloc::System;
let s = [10, 40, 30];
let x = s.to_vec_in(System);
// Here, `s` and `x` can be modified independently.
1.0.0 · Source
Converts self into a vector without clones or allocation.
The resulting vector can be converted back into a box via
Vec<T>’s into_boxed_slice method.
§ Examples
let s: Box<[i32]> = Box::new([10, 40, 30]);
let x = s.into_vec();
// `s` cannot be used anymore because it has been converted into `x`.
assert_eq!(x, vec![10, 40, 30]);
1.40.0 · Source
Creates a vector by copying a slice n times.
§ Panics
This function will panic if the capacity would overflow.
§ Examples
Basic usage:
assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
A panic upon overflow:
ⓘ
// this will panic at runtime
b"0123456789abcdef".repeat(usize::MAX);
1.0.0 · Source
Flattens a slice of T into a single value Self::Output.
§ Examples
assert_eq!(["hello", "world"].concat(), "helloworld");
assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
1.3.0 · Source
Flattens a slice of T into a single value Self::Output, placing a
given separator between each.
§ Examples
assert_eq!(["hello", "world"].join(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
1.0.0 · Source 👎Deprecated since 1.3.0: renamed to join
Flattens a slice of T into a single value Self::Output, placing a
given separator between each.
§ Examples
assert_eq!(["hello", "world"].connect(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
1.23.0 · Source
Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.
ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.
To uppercase the value in-place, use make_ascii_uppercase.
1.23.0 · Source
Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.
ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.
To lowercase the value in-place, use make_ascii_lowercase.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a mutable reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Converts this type into a shared reference of the (usually inferred) input type.
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Container type for copied ASCII characters.
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Checks if the value is within the ASCII range. Read more
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Makes a copy of the value in its ASCII upper case equivalent. Read more
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Makes a copy of the value in its ASCII lower case equivalent. Read more
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Checks that two values are an ASCII case-insensitive match. Read more
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Converts this type to its ASCII upper case equivalent in-place. Read more
Source § 👎Deprecated since 1.26.0: use inherent methods instead
Converts this type to its ASCII lower case equivalent in-place. Read more
1.4.0 · Source §1.0.0 · Source §Source §Source §1.4.0 · Source §1.0.0 · Source §Source §Source §1.0.0 · Source §
Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
Tells this buffer that amt bytes have been consumed from the buffer,
so they should no longer be returned in calls to read. Read more
Source §
🔬This is a nightly-only experimental API. ( buf_read_has_data_left #86423)
Checks if the underlying Read has any data left to be read. Read more
Reads all bytes into buf until the delimiter byte or EOF is reached. Read more
Skips all bytes until the delimiter byte or EOF is reached. Read more
Reads all bytes until a newline (the 0xA byte) is reached, and append
them to the provided String buffer. Read more
Returns an iterator over the contents of this reader split on the byte
byte. Read more
Returns an iterator over the lines of this reader. Read more
Copies source’s contents into self without creating a new allocation,
so long as the two are of the same length.
§ Examples
let x = Box::new([5, 6, 7]);
let mut y = Box::new([8, 9, 10]);
let yp: *const [i32] = &*y;
y.clone_from(&x);
// The value is the same
assert_eq!(x, y);
// And no allocation occurred
assert_eq!(yp, &*y);
Returns a copy of the value. Read more
Source §
🔬This is a nightly-only experimental API. ( clone_to_uninit #126799)
Performs copy-assignment from self to dst. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
Note: str in Concat<str> is not meaningful here.
This type parameter of the trait only exists to enable another impl.
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
1.0.0 · Source §1.0.0 · Source §1.5.0 · Source §
Creates a mutable empty slice.
1.0.0 · Source §1.21.0 · Source §
Allocates a reference-counted slice and fills it by cloning v’s items.
§ Example
let original: &[i32] = &[1, 2, 3];
let shared: Arc<[i32]> = Arc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);
Converts a &[T] into a Box<[T]>
This conversion allocates on the heap
and performs a copy of slice and its contents.
§ Examples
// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);
println!("{boxed_slice:?}");
Creates a Borrowed variant of Cow
from a slice.
This conversion does not allocate or clone the data.
Allocates a reference-counted slice and fills it by cloning v’s items.
§ Example
let original: &[i32] = &[1, 2, 3];
let shared: Rc<[i32]> = Rc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);
Allocates a Vec<T> and fills it by cloning s’s items.
§ Examples
assert_eq!(Vec::from(&[1, 2, 3][..]), vec![1, 2, 3]);
Creates a new BorrowedBuf from an uninitialized buffer.
Use set_init if part of the buffer is known to be already initialized.
Converts to this type from the input type.
Allocates a reference-counted slice and fills it by cloning v’s items.
§ Example
let mut original = [1, 2, 3];
let original: &mut [i32] = &mut original;
let shared: Arc<[i32]> = Arc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);
Converts a &mut [T] into a Box<[T]>
This conversion allocates on the heap
and performs a copy of slice and its contents.
§ Examples
// create a &mut [u8] which will be used to create a Box<[u8]>
let mut array = [104, 101, 108, 108, 111];
let slice: &mut [u8] = &mut array;
let boxed_slice: Box<[u8]> = Box::from(slice);
println!("{boxed_slice:?}");
Allocates a reference-counted slice and fills it by cloning v’s items.
§ Example
let mut original = [1, 2, 3];
let original: &mut [i32] = &mut original;
let shared: Rc<[i32]> = Rc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);
Allocates a Vec<T> and fills it by cloning s’s items.
§ Examples
assert_eq!(Vec::from(&mut [1, 2, 3][..]), vec![1, 2, 3]);
Creates a new BorrowedBuf from a fully initialized slice.
Converts to this type from the input type.
Converts a [T; N] into a Box<[T]>
This conversion moves the array to newly heap-allocated memory.
§ Examples
let boxed: Box<[u8]> = Box::from([4, 2]);
println!("{boxed:?}");
Converts to this type from the input type.
Converts a Box<str> into a Box<[u8]>
This conversion does not allocate on the heap and happens in place.
§ Examples
// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);
// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);
assert_eq!(boxed_slice, boxed_str);
Converts a Cow<'_, [T]> into a Box<[T]>
When cow is the Cow::Borrowed variant, this
conversion allocates on the heap and copies the
underlying slice. Otherwise, it will try to reuse the owned
Vec’s allocation.
Converts a vector into a boxed slice.
Before doing the conversion, this method discards excess capacity like Vec::shrink_to_fit.
§ Examples
assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());
Any excess capacity is removed:
let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3]);
assert_eq!(Box::from(vec), vec![1, 2, 3].into_boxed_slice());
Source §1.32.0 · Source §1.0.0 · Source §1.0.0 · Source §
The returned type after indexing.
Performs the indexing ( container[index]) operation. Read more
1.0.0 · Source §1.0.0 · Source §
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
Which kind of iterator are we turning this into?
The type of the elements being iterated over.
Creates an iterator from a value. Read more
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
Which kind of iterator are we turning this into?
The type of the elements being iterated over.
Creates an iterator from a value. Read more
Which kind of iterator are we turning this into?
The type of the elements being iterated over.
Creates an iterator from a value. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
The resulting type after concatenation
Source §
🔬This is a nightly-only experimental API. ( slice_concat_trait #27747)
1.0.0 · Source §1.0.0 · Source §
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient,
and should not be overridden without very good reason.
This method returns an ordering between self and other values if one exists. Read more
Tests less than (for self and other) and is used by the < operator. Read more
Tests less than or equal to (for self and other) and is used by the
<= operator. Read more
Tests greater than (for self and other) and is used by the >
operator. Read more
Tests greater than or equal to (for self and other) and is used by
the >= operator. Read more
Searches for chars that are equal to any of the char s in the slice.
§ Examples
assert_eq!("Hello world".find(&['o', 'l'][..]), Some(2));
assert_eq!("Hello world".find(&['h', 'w'][..]), Some(6));
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Associated searcher for this pattern
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Constructs the associated searcher from
self and the haystack to search in.
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Checks whether the pattern matches anywhere in the haystack
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Checks whether the pattern matches at the front of the haystack
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Removes the pattern from the front of haystack, if it matches.
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Checks whether the pattern matches at the back of the haystack
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Removes the pattern from the back of haystack, if it matches.
Source §
🔬This is a nightly-only experimental API. ( pattern #27721)
Returns the pattern as utf-8 bytes if possible.
Read is implemented for &[u8] by copying from the slice.
Note that reading updates the slice to point to the yet unread part. The slice will be empty when EOF is reached.
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
Source §
🔬This is a nightly-only experimental API. ( read_buf #78485)
Pull some bytes from this source into the specified buffer. Read more
Like read, except that it reads into a slice of buffers. Read more
Source §
🔬This is a nightly-only experimental API. ( can_vector #69941)
Determines if this Read er has an efficient read_vectored
implementation. Read more
Reads the exact number of bytes required to fill buf. Read more
Source §
🔬This is a nightly-only experimental API. ( read_buf #78485)
Reads the exact number of bytes required to fill cursor. Read more
Reads all bytes until EOF in this source, placing them into buf. Read more
Reads all bytes until EOF in this source, appending them to buf. Read more
Creates a “by reference” adaptor for this instance of Read. Read more
Transforms this Read instance to an Iterator over its bytes. Read more
Creates an adapter which will chain this stream with another. Read more
Creates an adapter which will read at most limit bytes from it. Read more
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if:
- the start of the range is greater than the end of the range or
- the end of the range is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if the start of the range is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if:
- the end of the range is
usize::MAXor - the start of the range is greater than the end of the range or
- the end of the range is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if the end of the range is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if the end of the range is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
The methods index and index_mut panic if the index is out of bounds.
The output type returned by methods.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
Source §
🔬This is a nightly-only experimental API. ( slice_pattern #56345)
The element type of the slice being matched on.
Source §
🔬This is a nightly-only experimental API. ( slice_pattern #56345)
Currently, the consumers of SlicePattern need a slice.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Returned iterator over socket addresses which this type may correspond to.
Tries to create an array ref &[T; N] from a slice ref &[T]. Succeeds if
slice.len() == N.
let bytes: [u8; 3] = [1, 0, 2];
let bytes_head: &[u8; 2] = <&[u8; 2]>::try_from(&bytes[0..2]).unwrap();
assert_eq!(1, u16::from_le_bytes(*bytes_head));
let bytes_tail: &[u8; 2] = bytes[1..3].try_into().unwrap();
assert_eq!(512, u16::from_le_bytes(*bytes_tail));
The type returned in the event of a conversion error.
Performs the conversion.
Tries to create an array [T; N] by copying from a slice &[T].
Succeeds if slice.len() == N.
let bytes: [u8; 3] = [1, 0, 2];
let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&bytes[0..2]).unwrap();
assert_eq!(1, u16::from_le_bytes(bytes_head));
let bytes_tail: [u8; 2] = bytes[1..3].try_into().unwrap();
assert_eq!(512, u16::from_le_bytes(bytes_tail));
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Tries to create a mutable array ref &mut [T; N] from a mutable slice ref
&mut [T]. Succeeds if slice.len() == N.
let mut bytes: [u8; 3] = [1, 0, 2];
let bytes_head: &mut [u8; 2] = <&mut [u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
assert_eq!(1, u16::from_le_bytes(*bytes_head));
let bytes_tail: &mut [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
assert_eq!(512, u16::from_le_bytes(*bytes_tail));
The type returned in the event of a conversion error.
Performs the conversion.
Tries to create an array [T; N] by copying from a mutable slice &mut [T].
Succeeds if slice.len() == N.
let mut bytes: [u8; 3] = [1, 0, 2];
let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
assert_eq!(1, u16::from_le_bytes(bytes_head));
let bytes_tail: [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
assert_eq!(512, u16::from_le_bytes(bytes_tail));
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Write is implemented for &mut [u8] by copying into the slice, overwriting
its data.
Note that writing updates the slice to point to the yet unwritten part. The slice will be empty when it has been completely overwritten.
If the number of bytes to be written exceeds the size of the slice, write operations will
return short writes: ultimately, Ok(0); in this situation, write_all returns an error of
kind ErrorKind::WriteZero.
Writes a buffer into this writer, returning how many bytes were written. Read more
Like write, except that it writes from a slice of buffers. Read more
Source §
🔬This is a nightly-only experimental API. ( can_vector #69941)
Source §
Attempts to write an entire buffer into this writer. Read more
Flushes this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
Source §
🔬This is a nightly-only experimental API. ( write_all_vectored #70436)
Attempts to write multiple buffers into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more
Creates a “by reference” adapter for this instance of Write. Read more
1.0.0 · Source §1.80.0 · Source §
This implementation is required to make sure that the &Box<[I]>: IntoIterator
implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.
This implementation is required to make sure that the &mut Box<[I]>: IntoIterator
implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.
1.80.0 · Source §1.80.0 · Source §
This implementation is required to make sure that the Box<[I]>: IntoIterator
implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.