std::slice - Rust
Description: API documentation for the Rust `slice` mod in crate `std`.
Keywords: rust, rustlang, rust-lang, slice

# 1.0.0[−][src]Module std::slice

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

See also the slice primitive type.

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"];

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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 x = &mut [1, 2, 3];
    x[1] = 7;
    assert_eq!(x, &[1, 7, 3]);

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Here are some of the things this module contains:

## Structs

There are several structs that are useful for slices, such as `Iter`, which represents iteration over a slice.

## Trait Implementations

There are several implementations of common traits for slices. Some examples include:

- `Clone`
- `Eq`, `Ord` - for slices whose element type are `Eq` or `Ord`.
- `Hash` - for slices whose element type is `Hash`.

## Iteration

The slices implement `IntoIterator`. The iterator yields references to the slice elements.

    let numbers = &[0, 1, 2];
    for n in numbers {
        println!("{} is a number!", n);
    }

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The mutable slice yields mutable references to the elements:

    let mut scores = [7, 8, 9];
    for score in &mut scores[..] {
        *score += 1;
    }

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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`.

- `.iter` and `.iter_mut` are the explicit methods to return the default iterators.
- Further methods that return iterators are `.split`, `.splitn`, `.chunks`, `.windows` and more.

## Structs

Chunks | An iterator over a slice in (non-overlapping) chunks (`chunk_size` elements at a time), starting at the beginning of the slice.
ChunksExact | An iterator over a slice in (non-overlapping) chunks (`chunk_size` elements at a time), starting at the beginning of the slice.
ChunksExactMut | An iterator over a slice in (non-overlapping) mutable chunks (`chunk_size` elements at a time), starting at the beginning of the slice.
ChunksMut | An iterator over a slice in (non-overlapping) mutable chunks (`chunk_size` elements at a time), starting at the beginning of the slice.
Iter | Immutable slice iterator
IterMut | Mutable slice iterator.
RChunks | An iterator over a slice in (non-overlapping) chunks (`chunk_size` elements at a time), starting at the end of the slice.
RChunksExact | An iterator over a slice in (non-overlapping) chunks (`chunk_size` elements at a time), starting at the end of the slice.
RChunksExactMut | An iterator over a slice in (non-overlapping) mutable chunks (`chunk_size` elements at a time), starting at the end of the slice.
RChunksMut | An iterator over a slice in (non-overlapping) mutable chunks (`chunk_size` elements at a time), starting at the end of the slice.
RSplit | An iterator over subslices separated by elements that match a predicate function, starting from the end of the slice.
RSplitMut | An iterator over the subslices of the vector which are separated by elements that match `pred`, starting from the end of the slice.
RSplitN | An iterator over subslices separated by elements that match a predicate function, limited to a given number of splits, starting from the end of the slice.
RSplitNMut | An iterator over subslices separated by elements that match a predicate function, limited to a given number of splits, starting from the end of the slice.
Split | An iterator over subslices separated by elements that match a predicate function.
SplitMut | An iterator over the mutable subslices of the vector which are separated by elements that match `pred`.
SplitN | An iterator over subslices separated by elements that match a predicate function, limited to a given number of splits.
SplitNMut | An iterator over subslices separated by elements that match a predicate function, limited to a given number of splits.
Windows | An iterator over overlapping subslices of length `size`.

## Traits

SliceIndex | A helper trait used for indexing operations.
Concat | Experimental Helper trait for `[T]::concat`.
Join | Experimental Helper trait for `[T]::join`

## Functions

from_mut | Converts a reference to T into a slice of length 1 (without copying).
from_raw_parts⚠ | Forms a slice from a pointer and a length.
from_raw_parts_mut⚠ | Performs the same functionality as `from_raw_parts`, except that a mutable slice is returned.
from_ref | Converts a reference to T into a slice of length 1 (without copying).