Primitive Type slice

A dynamically-sized view into a contiguous sequence, [T].

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]);

Methods

impl<T> [T]

pub fn len(&self) -> usize

Returns the number of elements in the slice.

Examples

let a = [1, 2, 3];
assert_eq!(a.len(), 3);

pub fn is_empty(&self) -> bool

Returns true if the slice has a length of 0.

Examples

let a = [1, 2, 3];
assert!(!a.is_empty());

pub fn first(&self) -> Option<&T>

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());

pub fn first_mut(&mut self) -> Option<&mut T>

Returns a mutable pointer 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]);

pub fn split_first(&self) -> Option<(&T, &[T])>

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]);
}

pub fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])>

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]);

pub fn split_last(&self) -> Option<(&T, &[T])>

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]);
}

pub fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])>

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]);

pub fn last(&self) -> Option<&T>

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());

pub fn last_mut(&mut self) -> Option<&mut T>

Returns a mutable pointer to the last item in the slice.

Examples

let x = &mut [0, 1, 2];

if let Some(last) = x.last_mut() {
    *last = 10;
}
assert_eq!(x, &[0, 1, 10]);

pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output> where
    I: SliceIndex<[T]>, 

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 None if out of bounds.
• If given a range, returns the subslice corresponding to that range, or None if 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));

pub fn get_mut<I>(
    &mut self,
    index: I
) -> Option<&mut <I as SliceIndex<[T]>>::Output> where
    I: SliceIndex<[T]>, 

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]);

pub unsafe fn get_unchecked<I>(
    &self,
    index: I
) -> &<I as SliceIndex<[T]>>::Output where
    I: SliceIndex<[T]>, 

Returns a reference to an element or subslice, without doing bounds checking.

This is generally not recommended, use with caution! For a safe alternative see get.

Examples

let x = &[1, 2, 4];

unsafe {
    assert_eq!(x.get_unchecked(1), &2);
}

pub unsafe fn get_unchecked_mut<I>(
    &mut self,
    index: I
) -> &mut <I as SliceIndex<[T]>>::Output where
    I: SliceIndex<[T]>, 

Returns a mutable reference to an element or subslice, without doing bounds checking.

This is generally not recommended, use with caution! For a safe alternative see get_mut.

Examples

let x = &mut [1, 2, 4];

unsafe {
    let elem = x.get_unchecked_mut(1);
    *elem = 13;
}
assert_eq!(x, &[1, 13, 4]);

pub const fn as_ptr(&self) -> *const T

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 pointing to garbage.

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));
    }
}

pub fn as_mut_ptr(&mut self) -> *mut T

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 pointing to garbage.

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]);

pub fn swap(&mut self, a: usize, b: usize)

Swaps two elements in the slice.

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"];
v.swap(1, 3);
assert!(v == ["a", "d", "c", "b"]);

pub fn reverse(&mut self)

Reverses the order of elements in the slice, in place.

Examples

let mut v = [1, 2, 3];
v.reverse();
assert!(v == [3, 2, 1]);

Important traits for Iter<'a, T>

impl<'a, T> Iterator for Iter<'a, T> type Item = &'a T;

pub fn iter(&self) -> Iter<T>

Returns an iterator over the slice.

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);

Important traits for IterMut<'a, T>

impl<'a, T> Iterator for IterMut<'a, T> type Item = &'a mut T;

pub fn iter_mut(&mut self) -> IterMut<T>

Returns an iterator that allows modifying each value.

Examples

let x = &mut [1, 2, 4];
for elem in x.iter_mut() {
    *elem += 2;
}
assert_eq!(x, &[3, 4, 6]);

Important traits for Windows<'a, T>

impl<'a, T> Iterator for Windows<'a, T> type Item = &'a [T];

pub fn windows(&self, size: usize) -> Windows<T>

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 0.

Examples

let slice = ['r', 'u', 's', 't'];
let mut iter = slice.windows(2);
assert_eq!(iter.next().unwrap(), &['r', 'u']);
assert_eq!(iter.next().unwrap(), &['u', 's']);
assert_eq!(iter.next().unwrap(), &['s', 't']);
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());

Important traits for Chunks<'a, T>

impl<'a, T> Iterator for Chunks<'a, T> type Item = &'a [T];

pub fn chunks(&self, chunk_size: usize) -> Chunks<T>

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 of the slice.

Panics

Panics if chunk_size is 0.

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());

Important traits for ChunksMut<'a, T>

impl<'a, T> Iterator for ChunksMut<'a, T> type Item = &'a mut [T];

pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<T>

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 of the slice.

Panics

Panics if chunk_size is 0.

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]);

Important traits for ChunksExact<'a, T>

impl<'a, T> Iterator for ChunksExact<'a, T> type Item = &'a [T];

pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<T>

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 0.

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']);

Important traits for ChunksExactMut<'a, T>

impl<'a, T> Iterator for ChunksExactMut<'a, T> type Item = &'a mut [T];

pub fn chunks_exact_mut(&mut self, chunk_size: usize) -> ChunksExactMut<T>

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 of the slice.

Panics

Panics if chunk_size is 0.

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]);

Important traits for RChunks<'a, T>

impl<'a, T> Iterator for RChunks<'a, T> type Item = &'a [T];

pub fn rchunks(&self, chunk_size: usize) -> RChunks<T>

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 0.

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());

Important traits for RChunksMut<'a, T>

impl<'a, T> Iterator for RChunksMut<'a, T> type Item = &'a mut [T];

pub fn rchunks_mut(&mut self, chunk_size: usize) -> RChunksMut<T>

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 0.

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]);

Important traits for RChunksExact<'a, T>

impl<'a, T> Iterator for RChunksExact<'a, T> type Item = &'a [T];

pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<T>

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 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 of the slice.

Panics

Panics if chunk_size is 0.

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']);

Important traits for RChunksExactMut<'a, T>

impl<'a, T> Iterator for RChunksExactMut<'a, T> type Item = &'a mut [T];

pub fn rchunks_exact_mut(&mut self, chunk_size: usize) -> RChunksExactMut<T>

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 of the slice.

Panics

Panics if chunk_size is 0.

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]);

pub fn split_at(&self, mid: usize) -> (&[T], &[T])

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.

Examples

let v = [1, 2, 3, 4, 5, 6];

{
   let (left, right) = v.split_at(0);
   assert!(left == []);
   assert!(right == [1, 2, 3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(2);
    assert!(left == [1, 2]);
    assert!(right == [3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(6);
    assert!(left == [1, 2, 3, 4, 5, 6]);
    assert!(right == []);
}

pub fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T])

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.

Examples

let mut v = [1, 0, 3, 0, 5, 6];
// scoped to restrict the lifetime of the borrows
{
    let (left, right) = v.split_at_mut(2);
    assert!(left == [1, 0]);
    assert!(right == [3, 0, 5, 6]);
    left[1] = 2;
    right[1] = 4;
}
assert!(v == [1, 2, 3, 4, 5, 6]);

Important traits for Split<'a, T, P>

impl<'a, T, P> Iterator for Split<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn split<F>(&self, pred: F) -> Split<T, F> where
    F: FnMut(&T) -> bool, 

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());

Important traits for SplitMut<'a, T, P>

impl<'a, T, P> Iterator for SplitMut<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a mut [T];

pub fn split_mut<F>(&mut self, pred: F) -> SplitMut<T, F> where
    F: FnMut(&T) -> bool, 

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]);

Important traits for RSplit<'a, T, P>

impl<'a, T, P> Iterator for RSplit<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn rsplit<F>(&self, pred: F) -> RSplit<T, F> where
    F: FnMut(&T) -> bool, 

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);

Important traits for RSplitMut<'a, T, P>

impl<'a, T, P> Iterator for RSplitMut<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a mut [T];

pub fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<T, F> where
    F: FnMut(&T) -> bool, 

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]);

Important traits for SplitN<'a, T, P>

impl<'a, T, P> Iterator for SplitN<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<T, F> where
    F: FnMut(&T) -> bool, 

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);
}

Important traits for SplitNMut<'a, T, P>

impl<'a, T, P> Iterator for SplitNMut<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a mut [T];

pub fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<T, F> where
    F: FnMut(&T) -> bool, 

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

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]);

Important traits for RSplitN<'a, T, P>

impl<'a, T, P> Iterator for RSplitN<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<T, F> where
    F: FnMut(&T) -> bool, 

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);
}

Important traits for RSplitNMut<'a, T, P>

impl<'a, T, P> Iterator for RSplitNMut<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a mut [T];

pub fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<T, F> where
    F: FnMut(&T) -> bool, 

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]);

pub fn contains(&self, x: &T) -> bool where
    T: PartialEq<T>, 

Returns true if the slice contains an element with the given value.

Examples

let v = [10, 40, 30];
assert!(v.contains(&30));
assert!(!v.contains(&50));

pub fn starts_with(&self, needle: &[T]) -> bool where
    T: PartialEq<T>, 

Returns true if needle is a prefix of the slice.

Examples

let v = [10, 40, 30];
assert!(v.starts_with(&[10]));
assert!(v.starts_with(&[10, 40]));
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(&[]));

pub fn ends_with(&self, needle: &[T]) -> bool where
    T: PartialEq<T>, 

Returns true if needle is a suffix of the slice.

Examples

let v = [10, 40, 30];
assert!(v.ends_with(&[30]));
assert!(v.ends_with(&[40, 30]));
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(&[]));

pub fn binary_search(&self, x: &T) -> Result<usize, usize> where
    T: Ord, 

Binary searches this sorted slice for a given element.

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. 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.

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, });

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> where
    F: FnMut(&'a T) -> Ordering, 

Binary searches this sorted slice with a comparator function.

The comparator function should implement an order consistent with the sort order of the underlying slice, returning an order code that indicates whether its argument is Less, Equal or Greater the desired target.

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. 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.

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, });

pub fn binary_search_by_key<'a, B, F>(
    &'a self,
    b: &B,
    f: F
) -> Result<usize, usize> where
    B: Ord,
    F: FnMut(&'a T) -> B, 

Binary searches this sorted 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 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. 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.

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, });

pub fn sort_unstable(&mut self) where
    T: Ord, 

Sorts the slice, but may not preserve the 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.

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

Examples

let mut v = [-5, 4, 1, -3, 2];

v.sort_unstable();
assert!(v == [-5, -3, 1, 2, 4]);

pub fn sort_unstable_by<F>(&mut self, compare: F) where
    F: FnMut(&T, &T) -> Ordering, 

Sorts the slice with a comparator function, but may not preserve the 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.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all a, b and c):

• total and antisymmetric: exactly one of a < b, a == b or a > b is true; and
• transitive, a < b and b < c implies a < c. The same must hold for both == and >.

For example, while f64 doesn't implement Ord because NaN != NaN, we can use partial_cmp as our sort function when we know the slice doesn't contain a NaN.

let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

Examples

let mut v = [5, 4, 1, 3, 2];
v.sort_unstable_by(|a, b| a.cmp(b));
assert!(v == [1, 2, 3, 4, 5]);

// reverse sorting
v.sort_unstable_by(|a, b| b.cmp(a));
assert!(v == [5, 4, 3, 2, 1]);

pub fn sort_unstable_by_key<K, F>(&mut self, f: F) where
    F: FnMut(&T) -> K,
    K: Ord, 

Sorts the slice with a key extraction function, but may not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(m n log(m n)) worst-case, where the key function is O(m).

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

Due to its key calling strategy, sort_unstable_by_key is likely to be slower than sort_by_cached_key in cases where the key function is expensive.

Examples

let mut v = [-5i32, 4, 1, -3, 2];

v.sort_unstable_by_key(|k| k.abs());
assert!(v == [1, 2, -3, 4, -5]);

pub fn partition_dedup(&mut self) -> (&mut [T], &mut [T]) where
    T: PartialEq<T>, 

🔬 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]);

pub fn partition_dedup_by<F>(&mut self, same_bucket: F) -> (&mut [T], &mut [T]) where
    F: FnMut(&mut T, &mut T) -> bool, 

🔬 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"]);

pub fn partition_dedup_by_key<K, F>(&mut self, key: F) -> (&mut [T], &mut [T]) where
    F: FnMut(&mut T) -> K,
    K: PartialEq<K>, 

🔬 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]);

pub fn rotate_left(&mut self, mid: usize)

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']);

pub fn rotate_right(&mut self, k: usize)

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']);

Rotate 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']);

pub fn clone_from_slice(&mut self, src: &[T]) where
    T: Clone, 

Copies the elements from src into self.

The length of src must be the same as self.

If src implements Copy, it can be more performant to use copy_from_slice.

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]);

pub fn copy_from_slice(&mut self, src: &[T]) where
    T: Copy, 

Copies all elements from src into self, using a memcpy.

The length of src must be the same as self.

If src 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]);

pub fn copy_within<R>(&mut self, src: R, dest: usize) where
    R: RangeBounds<usize>,
    T: Copy, 

🔬 This is a nightly-only experimental API. (copy_within #54236)

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!");

pub fn swap_with_slice(&mut self, other: &mut [T])

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]);

pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])

Transmute 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 method does a best effort to make the middle slice the greatest length possible for a given type and input slice, but only your algorithm's performance should depend on that, not its correctness.

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);
}

pub unsafe fn align_to_mut<U>(&mut self) -> (&mut [T], &mut [U], &mut [T])

Transmute 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 method does a best effort to make the middle slice the greatest length possible for a given type and input slice, but only your algorithm's performance should depend on that, not its correctness.

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);
}

pub fn is_sorted(&self) -> bool where
    T: PartialOrd<T>, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

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

#![feature(is_sorted)]
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, std::f32::NAN].is_sorted());

pub fn is_sorted_by<F>(&self, compare: F) -> bool where
    F: FnMut(&T, &T) -> Option<Ordering>, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

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 the ordering of two elements. Apart from that, it's equivalent to is_sorted; see its documentation for more information.

pub fn is_sorted_by_key<F, K>(&self, f: F) -> bool where
    F: FnMut(&T) -> K,
    K: PartialOrd<K>, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

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

#![feature(is_sorted)]

assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));

impl [u8]

pub fn is_ascii(&self) -> bool

Checks if all bytes in this slice are within the ASCII range.

pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool

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.

pub fn make_ascii_uppercase(&mut self)

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.

pub fn make_ascii_lowercase(&mut self)

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.

impl<T> [T]

pub fn sort(&mut self) where
    T: Ord, 

Sorts the slice.

This sort is stable (i.e., does not reorder equal elements) and O(n log n) worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See sort_unstable.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples

let mut v = [-5, 4, 1, -3, 2];

v.sort();
assert!(v == [-5, -3, 1, 2, 4]);

pub fn sort_by<F>(&mut self, compare: F) where
    F: FnMut(&T, &T) -> Ordering, 

Sorts the slice with a comparator function.

This sort is stable (i.e., does not reorder equal elements) and O(n log n) worst-case.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all a, b and c):

• total and antisymmetric: exactly one of a < b, a == b or a > b is true, and
• transitive, a < b and b < c implies a < c. The same must hold for both == and >.

For example, while f64 doesn't implement Ord because NaN != NaN, we can use partial_cmp as our sort function when we know the slice doesn't contain a NaN.

let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See sort_unstable_by.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples

let mut v = [5, 4, 1, 3, 2];
v.sort_by(|a, b| a.cmp(b));
assert!(v == [1, 2, 3, 4, 5]);

// reverse sorting
v.sort_by(|a, b| b.cmp(a));
assert!(v == [5, 4, 3, 2, 1]);

pub fn sort_by_key<K, F>(&mut self, f: F) where
    F: FnMut(&T) -> K,
    K: Ord, 

Sorts the slice with a key extraction function.

This sort is stable (i.e., does not reorder equal elements) and O(m n log(m n)) worst-case, where the key function is O(m).

For expensive key functions (e.g. functions that are not simple property accesses or basic operations), sort_by_cached_key is likely to be significantly faster, as it does not recompute element keys.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See sort_unstable_by_key.

Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of self, but for short slices a non-allocating insertion sort is used instead.

Examples

let mut v = [-5i32, 4, 1, -3, 2];

v.sort_by_key(|k| k.abs());
assert!(v == [1, 2, -3, 4, -5]);

pub fn sort_by_cached_key<K, F>(&mut self, f: F) where
    F: FnMut(&T) -> K,
    K: Ord, 

Sorts the slice with a key extraction function.

During sorting, the key function is called only once per element.

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).

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 algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

In the worst case, the algorithm allocates temporary storage in a Vec<(K, usize)> the length of the slice.

Examples

let mut v = [-5i32, 4, 32, -3, 2];

v.sort_by_cached_key(|k| k.to_string());
assert!(v == [-3, -5, 2, 32, 4]);

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_vec(&self) -> Vec<T> where
    T: Clone, 

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.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn into_vec(self: Box<[T]>) -> Vec<T>

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]);

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn repeat(&self, n: usize) -> Vec<T> where
    T: Copy, 

🔬 This is a nightly-only experimental API. (repeat_generic_slice #48784)

it's on str, why not on slice?

Creates a vector by repeating a slice n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

#![feature(repeat_generic_slice)]

fn main() {
    assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
}

A panic upon overflow:

#![feature(repeat_generic_slice)]
fn main() {
    // this will panic at runtime
    b"0123456789abcdef".repeat(usize::max_value());
}

impl [u8]

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_ascii_uppercase(&self) -> Vec<u8>

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.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_ascii_lowercase(&self) -> Vec<u8>

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.

Trait Implementations

impl<T> PartialOrd<[T]> for [T] where
    T: PartialOrd<T>, 

Implements comparison of vectors lexicographically.

fn partial_cmp(&self, other: &[T]) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

#[must_use]

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

#[must_use]

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

#[must_use]

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, T> IntoIterator for &'a mut [T]

type Item = &'a mut T

The type of the elements being iterated over.

type IntoIter = IterMut<'a, T>

Which kind of iterator are we turning this into?

Important traits for IterMut<'a, T>

impl<'a, T> Iterator for IterMut<'a, T> type Item = &'a mut T;

fn into_iter(self) -> IterMut<'a, T>

Creates an iterator from a value.

impl<'a, T> IntoIterator for &'a [T]

type Item = &'a T

The type of the elements being iterated over.

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?

Important traits for Iter<'a, T>

impl<'a, T> Iterator for Iter<'a, T> type Item = &'a T;

fn into_iter(self) -> Iter<'a, T>

Creates an iterator from a value.

impl<T> Ord for [T] where
    T: Ord, 

Implements comparison of vectors lexicographically.

fn cmp(&self, other: &[T]) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

impl<T, I> IndexMut<I> for [T] where
    I: SliceIndex<[T]>, 

fn index_mut(&mut self, index: I) -> &mut <I as SliceIndex<[T]>>::Output

Performs the mutable indexing (container[index]) operation.

impl<T, I> Index<I> for [T] where
    I: SliceIndex<[T]>, 

type Output = <I as SliceIndex<[T]>>::Output

The returned type after indexing.

fn index(&self, index: I) -> &<I as SliceIndex<[T]>>::Output

Performs the indexing (container[index]) operation.

impl<T> Eq for [T] where
    T: Eq, 

impl<T> Debug for [T] where
    T: Debug, 

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a, 'b, A, B> PartialEq<[A; 1]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 1]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 1]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 18]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 18]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 18]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 2]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 2]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 2]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 8]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 8]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 8]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 32]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 32]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 32]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 20]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 20]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 20]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 5]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 5]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 5]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 7]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 7]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 7]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 8]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 8]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 8]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 6]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 6]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 6]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 16]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 16]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 16]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 28]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 28]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 28]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 13]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 13]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 13]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 11]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 11]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 11]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 10]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 10]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 10]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 20]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 20]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 20]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 32]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 32]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 32]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 11]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 11]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 11]) -> bool

This method tests for !=.

impl<A, B> PartialEq<[B]> for [A] where
    A: PartialEq<B>, 

fn eq(&self, other: &[B]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[B]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 31]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 31]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 31]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 1]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 1]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 1]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 28]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 28]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 28]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 22]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 22]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 22]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 6]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 6]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 6]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 9]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 9]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 9]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 30]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 30]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 30]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 22]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 22]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 22]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 4]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 4]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 4]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 10]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 10]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 10]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 26]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 26]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 26]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 10]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 10]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 10]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 30]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 30]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 30]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 8]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 8]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 8]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 17]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 17]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 17]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 32]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 32]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 32]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 22]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 22]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 22]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 5]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 5]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 5]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 7]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 7]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 7]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 15]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 15]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 15]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 26]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 26]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 26]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 21]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 21]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 21]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 20]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 20]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 20]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 29]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 29]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 29]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 19]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 19]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 19]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 23]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 23]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 23]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 0]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 0]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 0]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 24]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 24]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 24]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 1]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 1]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 1]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 9]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 9]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 9]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 3]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 3]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 3]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 23]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 23]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 23]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 29]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 29]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 29]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 18]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 18]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 18]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 12]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 12]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 12]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 0]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 0]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 0]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 12]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 12]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 12]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 2]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 2]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 2]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 5]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 5]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 5]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 6]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 6]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 6]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 19]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 19]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 19]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 4]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 4]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 4]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 12]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 12]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 12]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 15]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 15]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 15]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 25]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 25]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 25]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 29]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 29]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 29]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 27]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 27]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 27]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 3]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 3]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 3]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 18]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 18]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 18]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 14]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 14]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 14]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 19]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 19]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 19]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 21]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 21]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 21]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 3]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 3]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 3]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 13]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 13]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 13]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 31]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 31]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 31]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 28]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 28]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 28]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 27]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 27]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 27]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 0]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 0]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 0]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 30]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 30]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 30]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 14]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 14]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 14]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 21]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 21]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 21]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 11]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 11]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 11]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 25]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 25]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 25]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 7]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 7]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 7]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 24]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 24]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 24]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 27]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 27]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 27]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 2]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 2]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 2]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 24]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 24]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 24]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 9]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 9]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 9]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 31]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 31]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 31]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 14]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 14]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 14]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 16]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 16]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 16]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 4]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 4]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 4]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 23]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 23]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 23]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 16]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 16]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 16]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 17]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 17]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 17]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 25]> for &'b mut [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 25]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 25]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 15]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 15]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 15]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 13]> for &'b [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 13]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 13]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 26]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 26]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 26]) -> bool

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<[A; 17]> for [B] where
    B: PartialEq<A>, 

fn eq(&self, other: &[A; 17]) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &[A; 17]) -> bool

This method tests for !=.

impl<T> AsMut<[T]> for [T]

Important traits for &'_ [u8]

impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]

fn as_mut(&mut self) -> &mut [T]

Performs the conversion.

impl<'a, 'b> Pattern<'a> for &'b [char]

Searches for chars that are equal to any of the chars in the array

type Searcher = CharSliceSearcher<'a, 'b>

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Associated searcher for this pattern

fn into_searcher(self, haystack: &'a str) -> CharSliceSearcher<'a, 'b>

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Constructs the associated searcher from self and the haystack to search in.

fn is_contained_in(self, haystack: &'a str) -> bool

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches anywhere in the haystack

fn is_prefix_of(self, haystack: &'a str) -> bool

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches at the front of the haystack

fn is_suffix_of(self, haystack: &'a str) -> bool where
    CharSliceSearcher<'a, 'b>: ReverseSearcher<'a>, 

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches at the back of the haystack

impl<T> AsRef<[T]> for [T]

Important traits for &'_ [u8]

impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]

fn as_ref(&self) -> &[T]

Performs the conversion.

impl<'_, T> Default for &'_ mut [T]

Important traits for &'_ [u8]

impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]

fn default() -> &'_ mut [T]

Creates a mutable empty slice.

impl<'_, T> Default for &'_ [T]

Important traits for &'_ [u8]

impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]

fn default() -> &'_ [T]

Creates an empty slice.

impl<T> Hash for [T] where
    T: Hash, 

fn hash<H>(&self, state: &mut H) where
    H: Hasher, 

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl<T> ToOwned for [T] where
    T: Clone, 

type Owned = Vec<T>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn to_owned(&self) -> Vec<T>

Creates owned data from borrowed data, usually by cloning.

fn clone_into(&self, target: &mut Vec<T>)

🔬 This is a nightly-only experimental API. (toowned_clone_into #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning.

impl<S> SliceConcatExt<str> for [S] where
    S: Borrow<str>, 

type Output = String

🔬 This is a nightly-only experimental API. (slice_concat_ext #27747)

trait should not have to exist

The resulting type after concatenation

fn concat(&self) -> String

Flattens a slice of T into a single value Self::Output.

fn join(&self, sep: &str) -> String

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

fn connect(&self, sep: &str) -> String

Deprecated since 1.3.0:

renamed to join

impl<T, V> SliceConcatExt<T> for [V] where
    T: Clone,
    V: Borrow<[T]>, 

type Output = Vec<T>

🔬 This is a nightly-only experimental API. (slice_concat_ext #27747)

trait should not have to exist

The resulting type after concatenation

Important traits for Vec<u8>

impl Write for Vec<u8>

fn concat(&self) -> Vec<T>

Flattens a slice of T into a single value Self::Output.

Important traits for Vec<u8>

impl Write for Vec<u8>

fn join(&self, sep: &T) -> Vec<T>

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

Important traits for Vec<u8>

impl Write for Vec<u8>

fn connect(&self, sep: &T) -> Vec<T>

Deprecated since 1.3.0:

renamed to join

impl AsciiExt for [u8]

type Owned = Vec<u8>

Deprecated since 1.26.0:

use inherent methods instead

Container type for copied ASCII characters.

fn is_ascii(&self) -> bool

Deprecated since 1.26.0:

use inherent methods instead

Checks if the value is within the ASCII range.

fn to_ascii_uppercase(&self) -> Self::Owned

Deprecated since 1.26.0:

use inherent methods instead

Makes a copy of the value in its ASCII upper case equivalent.

fn to_ascii_lowercase(&self) -> Self::Owned

Deprecated since 1.26.0:

use inherent methods instead

Makes a copy of the value in its ASCII lower case equivalent.

fn eq_ignore_ascii_case(&self, o: &Self) -> bool

Deprecated since 1.26.0:

use inherent methods instead

Checks that two values are an ASCII case-insensitive match.

fn make_ascii_uppercase(&mut self)

Deprecated since 1.26.0:

use inherent methods instead

Converts this type to its ASCII upper case equivalent in-place.

fn make_ascii_lowercase(&mut self)

Deprecated since 1.26.0:

use inherent methods instead

Converts this type to its ASCII lower case equivalent in-place.

impl<'_> Read for &'_ [u8]

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.

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoVecMut]) -> Result<usize>

🔬 This is a nightly-only experimental API. (iovec #58452)

Like read, except that it reads into a slice of buffers.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer #42788)

Determines if this Reader can work with buffers of uninitialized memory.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill buf.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to buf.

Important traits for &'_ mut I

impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized,  type Output = <F as Future>::Output;impl<R: Read + ?Sized, '_> Read for &'_ mut Rimpl<W: Write + ?Sized, '_> Write for &'_ mut W

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a "by reference" adaptor for this instance of Read.

Important traits for Bytes<R>

impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;

fn bytes(self) -> Bytes<Self> where
    Self: Sized, 

Transforms this Read instance to an [Iterator] over its bytes.

Important traits for Chain<T, U>

impl<T: Read, U: Read> Read for Chain<T, U>

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where
    Self: Sized, 

Creates an adaptor which will chain this stream with another.

Important traits for Take<T>

impl<T: Read> Read for Take<T>

fn take(self, limit: u64) -> Take<Self> where
    Self: Sized, 

Creates an adaptor which will read at most limit bytes from it.

impl<'_> Write for &'_ mut [u8]

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.

fn write(&mut self, data: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoVec]) -> Result<usize>

🔬 This is a nightly-only experimental API. (iovec #58452)

Like write, except that it writes from a slice of buffers.

fn write_all(&mut self, data: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_fmt(&mut self, fmt: Arguments) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

Important traits for &'_ mut I

impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized,  type Output = <F as Future>::Output;impl<R: Read + ?Sized, '_> Read for &'_ mut Rimpl<W: Write + ?Sized, '_> Write for &'_ mut W

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a "by reference" adaptor for this instance of Write.

impl<'_> BufRead for &'_ [u8]

fn fill_buf(&mut self) -> Result<&[u8]>

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(&mut self, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to read.

fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes into buf until the delimiter byte or EOF is reached.

fn read_line(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer.

Important traits for Split<B>

impl<B: BufRead> Iterator for Split<B> type Item = Result<Vec<u8>>;

fn split(self, byte: u8) -> Split<Self> where
    Self: Sized, 

Returns an iterator over the contents of this reader split on the byte byte.

Important traits for Lines<B>

impl<B: BufRead> Iterator for Lines<B> type Item = Result<String>;

fn lines(self) -> Lines<Self> where
    Self: Sized, 

Returns an iterator over the lines of this reader.

impl<'a> ToSocketAddrs for &'a [SocketAddr]

type Iter = Cloned<Iter<'a, SocketAddr>>

Returned iterator over socket addresses which this type may correspond to.

fn to_socket_addrs(&self) -> Result<Self::Iter>

Converts this object to an iterator of resolved SocketAddrs.