array - Rust
Description: A fixed-size array, denoted `[T; N]`, for the element type, `T`, and the non-negative compile-time constant size, `N`.

## array

# Primitive Type array

1.0.0
Expand description

A fixed-size array, denoted `[T; N]`, for the element type, `T`, and the non-negative compile-time constant size, `N`.

There are two syntactic forms for creating an array:

- A list with each element, i.e., `[x, y, z]`.

- A repeat expression `[expr; N]` where `N` is how many times to repeat `expr` in the array. `expr` must either be:

  - A value of a type implementing the `Copy` trait
  - A `const` value

Note that `[expr; 0]` is allowed, and produces an empty array. This will still evaluate `expr`, however, and immediately drop the resulting value, so be mindful of side effects.

Arrays of any size implement the following traits if the element type allows it:

- `Copy`
- `Clone`
- `Debug`
- `IntoIterator` (implemented for `[T; N]`, `&[T; N]` and `&mut [T; N]`)
- `PartialEq`, `PartialOrd`, `Eq`, `Ord`
- `Hash`
- `AsRef`, `AsMut`
- `Borrow`, `BorrowMut`

Arrays of sizes from 0 to 32 (inclusive) implement the `Default` trait if the element type allows it. As a stopgap, trait implementations are statically generated up to size 32.

Arrays of sizes from 1 to 12 (inclusive) implement `From<Tuple>`, where `Tuple` is a homogeneous tuple of appropriate length.

Arrays coerce to slices (`[T]`), so a slice method may be called on an array. Indeed, this provides most of the API for working with arrays.

Slices have a dynamic size and do not coerce to arrays. Instead, use `slice.try_into().unwrap()` or `<ArrayType>::try_from(slice).unwrap()`.

Array’s `try_from(slice)` implementations (and the corresponding `slice.try_into()` array implementations) succeed if the input slice length is the same as the result array length. They optimize especially well when the optimizer can easily determine the slice length, e.g. `<[u8; 4]>::try_from(&slice[4..8]).unwrap()`. Array implements TryFrom returning:

- `[T; N]` copies from the slice’s elements
- `&[T; N]` references the original slice’s elements
- `&mut [T; N]` references the original slice’s elements

You can move elements out of an array with a slice pattern. If you want one element, see `mem::replace`.

## §Examples

    let mut array: [i32; 3] = [0; 3];

    array[1] = 1;
    array[2] = 2;

    assert_eq!([1, 2], &array[1..]);

    // This loop prints: 0 1 2
    for x in array {
        print!("{x} ");
    }

You can also iterate over reference to the array’s elements:

    let array: [i32; 3] = [0; 3];

    for x in &array { }

You can use `<ArrayType>::try_from(slice)` or `slice.try_into()` to get an array from a slice:

    let bytes: [u8; 3] = [1, 0, 2];
    assert_eq!(1, u16::from_le_bytes(<[u8; 2]>::try_from(&bytes[0..2]).unwrap()));
    assert_eq!(512, u16::from_le_bytes(bytes[1..3].try_into().unwrap()));

You can use a slice pattern to move elements out of an array:

    fn move_away(_: String) { /* Do interesting things. */ }

    let [john, roa] = ["John".to_string(), "Roa".to_string()];
    move_away(john);
    move_away(roa);

Arrays can be created from homogeneous tuples of appropriate length:

    let tuple: (u32, u32, u32) = (1, 2, 3);
    let array: [u32; 3] = tuple.into();

## §Editions

Prior to Rust 1.53, arrays did not implement `IntoIterator` by value, so the method call `array.into_iter()` auto-referenced into a slice iterator. Right now, the old behavior is preserved in the 2015 and 2018 editions of Rust for compatibility, ignoring `IntoIterator` by value. In the future, the behavior on the 2015 and 2018 edition might be made consistent to the behavior of later editions.

ⓘ

    // Rust 2015 and 2018:

    let array: [i32; 3] = [0; 3];

    // This creates a slice iterator, producing references to each value.
    for item in array.into_iter().enumerate() {
        let (i, x): (usize, &i32) = item;
        println!("array[{i}] = {x}");
    }

    // The `array_into_iter` lint suggests this change for future compatibility:
    for item in array.iter().enumerate() {
        let (i, x): (usize, &i32) = item;
        println!("array[{i}] = {x}");
    }

    // You can explicitly iterate an array by value using `IntoIterator::into_iter`
    for item in IntoIterator::into_iter(array).enumerate() {
        let (i, x): (usize, i32) = item;
        println!("array[{i}] = {x}");
    }

Starting in the 2021 edition, `array.into_iter()` uses `IntoIterator` normally to iterate by value, and `iter()` should be used to iterate by reference like previous editions.

ⓘ

    // Rust 2021:

    let array: [i32; 3] = [0; 3];

    // This iterates by reference:
    for item in array.iter().enumerate() {
        let (i, x): (usize, &i32) = item;
        println!("array[{i}] = {x}");
    }

    // This iterates by value:
    for item in array.into_iter().enumerate() {
        let (i, x): (usize, i32) = item;
        println!("array[{i}] = {x}");
    }

Future language versions might start treating the `array.into_iter()` syntax on editions 2015 and 2018 the same as on edition 2021. So code using those older editions should still be written with this change in mind, to prevent breakage in the future. The safest way to accomplish this is to avoid the `into_iter` syntax on those editions. If an edition update is not viable/desired, there are multiple alternatives:

- use `iter`, equivalent to the old behavior, creating references
- use `IntoIterator::into_iter`, equivalent to the post-2021 behavior (Rust 1.53+)
- replace `for ... in array.into_iter() {` with `for ... in array {`, equivalent to the post-2021 behavior (Rust 1.53+)

ⓘ

    // Rust 2015 and 2018:

    let array: [i32; 3] = [0; 3];

    // This iterates by reference:
    for item in array.iter() {
        let x: &i32 = item;
        println!("{x}");
    }

    // This iterates by value:
    for item in IntoIterator::into_iter(array) {
        let x: i32 = item;
        println!("{x}");
    }

    // This iterates by value:
    for item in array {
        let x: i32 = item;
        println!("{x}");
    }

    // IntoIter can also start a chain.
    // This iterates by value:
    for item in IntoIterator::into_iter(array).enumerate() {
        let (i, x): (usize, i32) = item;
        println!("array[{i}] = {x}");
    }

## Implementations§

Source§

### impl<T, const N: usize> [MaybeUninit<T>; N]

Source

#### pub const fn transpose(self) -> MaybeUninit<[T; N]>

🔬This is a nightly-only experimental API. (`maybe_uninit_uninit_array_transpose` #96097)

Transposes a `[MaybeUninit<T>; N]` into a `MaybeUninit<[T; N]>`.

##### §Examples

    #![feature(maybe_uninit_uninit_array_transpose)]

    let data = [MaybeUninit::<u8>::uninit(); 1000];
    let data: MaybeUninit<[u8; 1000]> = data.transpose();

Source§

### impl<const N: usize> [u8; N]

Source

#### pub const fn as_ascii(&self) -> Option<&[Char; N]>

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

Converts this array of bytes into an array of ASCII characters, or returns `None` if any of the characters is non-ASCII.

##### §Examples

    #![feature(ascii_char)]

    const HEX_DIGITS: [std::ascii::Char; 16] =
        *b"0123456789abcdef".as_ascii().unwrap();

    assert_eq!(HEX_DIGITS[1].as_str(), "1");
    assert_eq!(HEX_DIGITS[10].as_str(), "a");

Source

#### pub const unsafe fn as_ascii_unchecked(&self) -> &[Char; N]

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

Converts this array of bytes into an array of ASCII characters, without checking whether they’re valid.

##### §Safety

Every byte in the array must be in `0..=127`, or else this is UB.

Source§

### impl<T, const N: usize> [T; N]

1.55.0 (const: unstable) · Source

#### pub fn map<F, U>(self, f: F) -> [U; N]
where F: FnMut(T) -> U, U:, T:,

Returns an array of the same size as `self`, with function `f` applied to each element in order.

If you don’t necessarily need a new fixed-size array, consider using `Iterator::map` instead.

##### §Note on performance and stack usage

Unfortunately, usages of this method are currently not always optimized as well as they could be. This mainly concerns large arrays, as mapping over small arrays seem to be optimized just fine. Also note that in debug mode (i.e. without any optimizations), this method can use a lot of stack space (a few times the size of the array or more).

Therefore, in performance-critical code, try to avoid using this method on large arrays or check the emitted code. Also try to avoid chained maps (e.g. `arr.map(...).map(...)`).

In many cases, you can instead use `Iterator::map` by calling `.iter()` or `.into_iter()` on your array. `[T; N]::map` is only necessary if you really need a new array of the same size as the result. Rust’s lazy iterators tend to get optimized very well.

##### §Examples

    let x = [1, 2, 3];
    let y = x.map(|v| v + 1);
    assert_eq!(y, [2, 3, 4]);

    let x = [1, 2, 3];
    let mut temp = 0;
    let y = x.map(|v| { temp += 1; v * temp });
    assert_eq!(y, [1, 4, 9]);

    let x = ["Ferris", "Bueller's", "Day", "Off"];
    let y = x.map(|v| v.len());
    assert_eq!(y, [6, 9, 3, 3]);

Source

#### pub const fn try_map<R>( self, f: impl FnMut(T) -> R, ) -> <R::Residual as Residual<[R::Output; N]>>::TryType
where R: Try<Residual: Residual<[R::Output; N]>, Output>, T:,

🔬This is a nightly-only experimental API. (`array_try_map` #79711)

A fallible function `f` applied to each element on array `self` in order to return an array the same size as `self` or the first error encountered.

The return type of this function depends on the return type of the closure. If you return `Result<T, E>` from the closure, you’ll get a `Result<[T; N], E>`. If you return `Option<T>` from the closure, you’ll get an `Option<[T; N]>`.

##### §Examples

    #![feature(array_try_map)]

    let a = ["1", "2", "3"];
    let b = a.try_map(|v| v.parse::<u32>()).unwrap().map(|v| v + 1);
    assert_eq!(b, [2, 3, 4]);

    let a = ["1", "2a", "3"];
    let b = a.try_map(|v| v.parse::<u32>());
    assert!(b.is_err());

    use std::num::NonZero;

    let z = [1, 2, 0, 3, 4];
    assert_eq!(z.try_map(NonZero::new), None);

    let a = [1, 2, 3];
    let b = a.try_map(NonZero::new);
    let c = b.map(|x| x.map(NonZero::get));
    assert_eq!(c, Some(a));

1.57.0 (const: 1.57.0) · Source

#### pub const fn as_slice(&self) -> &[T]

Returns a slice containing the entire array. Equivalent to `&s[..]`.

1.57.0 (const: 1.89.0) · Source

#### pub const fn as_mut_slice(&mut self) -> &mut [T]

Returns a mutable slice containing the entire array. Equivalent to `&mut s[..]`.

1.77.0 (const: 1.91.0) · Source

#### pub const fn each_ref(&self) -> [&T; N]

Borrows each element and returns an array of references with the same size as `self`.

##### §Example

    let floats = [3.1, 2.7, -1.0];
    let float_refs: [&f64; 3] = floats.each_ref();
    assert_eq!(float_refs, [&3.1, &2.7, &-1.0]);

This method is particularly useful if combined with other methods, like `map`. This way, you can avoid moving the original array if its elements are not `Copy`.

    let strings = ["Ferris".to_string(), "♥".to_string(), "Rust".to_string()];
    let is_ascii = strings.each_ref().map(|s| s.is_ascii());
    assert_eq!(is_ascii, [true, false, true]);

    // We can still access the original array: it has not been moved.
    assert_eq!(strings.len(), 3);

1.77.0 (const: 1.91.0) · Source

#### pub const fn each_mut(&mut self) -> [&mut T; N]

Borrows each element mutably and returns an array of mutable references with the same size as `self`.

##### §Example

    let mut floats = [3.1, 2.7, -1.0];
    let float_refs: [&mut f64; 3] = floats.each_mut();
    *float_refs[0] = 0.0;
    assert_eq!(float_refs, [&mut 0.0, &mut 2.7, &mut -1.0]);
    assert_eq!(floats, [0.0, 2.7, -1.0]);

Source

#### pub fn split_array_ref<const M: usize>(&self) -> (&[T; M], &[T])

🔬This is a nightly-only experimental API. (`split_array` #90091)

Divides one array reference into two at an index.

The first will contain all indices from `[0, M)` (excluding the index `M` itself) and the second will contain all indices from `[M, N)` (excluding the index `N` itself).

##### §Panics

Panics if `M > N`.

##### §Examples

    #![feature(split_array)]

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

    {
       let (left, right) = v.split_array_ref::<0>();
       assert_eq!(left, &[]);
       assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_array_ref::<2>();
        assert_eq!(left, &[1, 2]);
        assert_eq!(right, &[3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_array_ref::<6>();
        assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
        assert_eq!(right, &[]);
    }

Source

#### pub fn split_array_mut<const M: usize>(&mut self) -> (&mut [T; M], &mut [T])

🔬This is a nightly-only experimental API. (`split_array` #90091)

Divides one mutable array reference into two at an index.

The first will contain all indices from `[0, M)` (excluding the index `M` itself) and the second will contain all indices from `[M, N)` (excluding the index `N` itself).

##### §Panics

Panics if `M > N`.

##### §Examples

    #![feature(split_array)]

    let mut v = [1, 0, 3, 0, 5, 6];
    let (left, right) = v.split_array_mut::<2>();
    assert_eq!(left, &mut [1, 0][..]);
    assert_eq!(right, &mut [3, 0, 5, 6]);
    left[1] = 2;
    right[1] = 4;
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

Source

#### pub fn rsplit_array_ref<const M: usize>(&self) -> (&[T], &[T; M])

🔬This is a nightly-only experimental API. (`split_array` #90091)

Divides one array reference into two at an index from the end.

The first will contain all indices from `[0, N - M)` (excluding the index `N - M` itself) and the second will contain all indices from `[N - M, N)` (excluding the index `N` itself).

##### §Panics

Panics if `M > N`.

##### §Examples

    #![feature(split_array)]

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

    {
       let (left, right) = v.rsplit_array_ref::<0>();
       assert_eq!(left, &[1, 2, 3, 4, 5, 6]);
       assert_eq!(right, &[]);
    }

    {
        let (left, right) = v.rsplit_array_ref::<2>();
        assert_eq!(left, &[1, 2, 3, 4]);
        assert_eq!(right, &[5, 6]);
    }

    {
        let (left, right) = v.rsplit_array_ref::<6>();
        assert_eq!(left, &[]);
        assert_eq!(right, &[1, 2, 3, 4, 5, 6]);
    }

Source

#### pub fn rsplit_array_mut<const M: usize>(&mut self) -> (&mut [T], &mut [T; M])

🔬This is a nightly-only experimental API. (`split_array` #90091)

Divides one mutable array reference into two at an index from the end.

The first will contain all indices from `[0, N - M)` (excluding the index `N - M` itself) and the second will contain all indices from `[N - M, N)` (excluding the index `N` itself).

##### §Panics

Panics if `M > N`.

##### §Examples

    #![feature(split_array)]

    let mut v = [1, 0, 3, 0, 5, 6];
    let (left, right) = v.rsplit_array_mut::<4>();
    assert_eq!(left, &mut [1, 0]);
    assert_eq!(right, &mut [3, 0, 5, 6][..]);
    left[1] = 2;
    right[1] = 4;
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

Source§

### impl<T, const N: usize> [Option<T>; N]

Source

#### pub fn transpose(self) -> Option<[T; N]>

🔬This is a nightly-only experimental API. (`option_array_transpose` #130828)

Transposes a `[Option<T>; N]` into a `Option<[T; N]>`.

##### §Examples

    #![feature(option_array_transpose)]

    let data = [Some(0); 1000];
    let data: Option<[u8; 1000]> = data.transpose();
    assert_eq!(data, Some([0; 1000]));

    let data = [Some(0), None];
    let data: Option<[u8; 2]> = data.transpose();
    assert_eq!(data, None);

## Trait Implementations§

1.0.0 (const: unstable) · Source§

### impl<T, const N: usize> AsMut<[T]> for [T; N]

Source§

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

Converts this type into a mutable reference of the (usually inferred) input type.
Source§

### impl<T, const N: usize> AsMut<[T; N]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

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

Converts this type into a mutable reference of the (usually inferred) input type.
1.0.0 (const: unstable) · Source§

### impl<T, const N: usize> AsRef<[T]> for [T; N]

Source§

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

Converts this type into a shared reference of the (usually inferred) input type.
Source§

### impl<T, const N: usize> AsRef<[T; N]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### fn as_ref(&self) -> &[T; N]

Converts this type into a shared reference of the (usually inferred) input type.
1.4.0 (const: unstable) · Source§

### impl<T, const N: usize> Borrow<[T]> for [T; N]

Source§

#### fn borrow(&self) -> &[T]

Immutably borrows from an owned value. Read more
1.4.0 (const: unstable) · Source§

### impl<T, const N: usize> BorrowMut<[T]> for [T; N]

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#### fn borrow_mut(&mut self) -> &mut [T]

Mutably borrows from an owned value. Read more
1.58.0 · Source§

### impl<T: Clone, const N: usize> Clone for [T; N]

Source§

#### fn clone(&self) -> Self

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, other: &Self)

Performs copy-assignment from `source`. Read more
1.0.0 · Source§

### impl<T: Debug, const N: usize> Debug for [T; N]

Source§

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.4.0 · Source§

### impl<T> Default for [T; 31]
where T: Default,

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#### fn default() -> [T; 31]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 30]
where T: Default,

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#### fn default() -> [T; 30]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 21]
where T: Default,

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#### fn default() -> [T; 21]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 20]
where T: Default,

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#### fn default() -> [T; 20]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 19]
where T: Default,

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#### fn default() -> [T; 19]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 18]
where T: Default,

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#### fn default() -> [T; 18]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 17]
where T: Default,

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#### fn default() -> [T; 17]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 16]
where T: Default,

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#### fn default() -> [T; 16]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 15]
where T: Default,

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#### fn default() -> [T; 15]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 14]
where T: Default,

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#### fn default() -> [T; 14]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 13]
where T: Default,

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#### fn default() -> [T; 13]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 12]
where T: Default,

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#### fn default() -> [T; 12]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 29]
where T: Default,

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#### fn default() -> [T; 29]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 11]
where T: Default,

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#### fn default() -> [T; 11]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 10]
where T: Default,

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#### fn default() -> [T; 10]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 9]
where T: Default,

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#### fn default() -> [T; 9]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 8]
where T: Default,

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#### fn default() -> [T; 8]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 7]
where T: Default,

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#### fn default() -> [T; 7]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 6]
where T: Default,

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#### fn default() -> [T; 6]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 5]
where T: Default,

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#### fn default() -> [T; 5]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 4]
where T: Default,

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#### fn default() -> [T; 4]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 3]
where T: Default,

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#### fn default() -> [T; 3]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 2]
where T: Default,

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#### fn default() -> [T; 2]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 28]
where T: Default,

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#### fn default() -> [T; 28]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 1]
where T: Default,

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#### fn default() -> [T; 1]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 0]

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#### fn default() -> [T; 0]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 27]
where T: Default,

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#### fn default() -> [T; 27]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 26]
where T: Default,

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#### fn default() -> [T; 26]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 25]
where T: Default,

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#### fn default() -> [T; 25]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 24]
where T: Default,

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#### fn default() -> [T; 24]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 23]
where T: Default,

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#### fn default() -> [T; 23]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 22]
where T: Default,

Source§

#### fn default() -> [T; 22]

Returns the “default value” for a type. Read more
1.4.0 · Source§

### impl<T> Default for [T; 32]
where T: Default,

Source§

#### fn default() -> [T; 32]

Returns the “default value” for a type. Read more
1.71.0 · Source§

### impl<T> From<[T; N]> for (T₁, T₂, …, Tₙ)

This trait is implemented for tuples up to twelve items long.

Source§

#### fn from(array: [T; 1]) -> Self

Converts to this type from the input type.
Source§

### impl<T, const N: usize> From<[T; N]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### fn from(array: [T; N]) -> Self

Converts to this type from the input type.
Source§

### impl<T, const N: usize> From<[bool; N]> for Mask<T, N>
where T: MaskElement, LaneCount<N>: SupportedLaneCount,

Source§

#### fn from(array: [bool; N]) -> Self

Converts to this type from the input type.
1.17.0 (const: unstable) · Source§

### impl From<[u16; 8]> for IpAddr

Source§

#### fn from(segments: [u16; 8]) -> IpAddr

Creates an `IpAddr::V6` from an eight element 16-bit array.

##### §Examples

    use std::net::{IpAddr, Ipv6Addr};

    let addr = IpAddr::from([
        0x20du16, 0x20cu16, 0x20bu16, 0x20au16,
        0x209u16, 0x208u16, 0x207u16, 0x206u16,
    ]);
    assert_eq!(
        IpAddr::V6(Ipv6Addr::new(
            0x20d, 0x20c, 0x20b, 0x20a,
            0x209, 0x208, 0x207, 0x206,
        )),
        addr
    );

1.16.0 (const: unstable) · Source§

### impl From<[u16; 8]> for Ipv6Addr

Source§

#### fn from(segments: [u16; 8]) -> Ipv6Addr

Creates an `Ipv6Addr` from an eight element 16-bit array.

##### §Examples

    use std::net::Ipv6Addr;

    let addr = Ipv6Addr::from([
        0x20du16, 0x20cu16, 0x20bu16, 0x20au16,
        0x209u16, 0x208u16, 0x207u16, 0x206u16,
    ]);
    assert_eq!(
        Ipv6Addr::new(
            0x20d, 0x20c, 0x20b, 0x20a,
            0x209, 0x208, 0x207, 0x206,
        ),
        addr
    );

1.17.0 (const: unstable) · Source§

### impl From<[u8; 16]> for IpAddr

Source§

#### fn from(octets: [u8; 16]) -> IpAddr

Creates an `IpAddr::V6` from a sixteen element byte array.

##### §Examples

    use std::net::{IpAddr, Ipv6Addr};

    let addr = IpAddr::from([
        0x19u8, 0x18u8, 0x17u8, 0x16u8, 0x15u8, 0x14u8, 0x13u8, 0x12u8,
        0x11u8, 0x10u8, 0x0fu8, 0x0eu8, 0x0du8, 0x0cu8, 0x0bu8, 0x0au8,
    ]);
    assert_eq!(
        IpAddr::V6(Ipv6Addr::new(
            0x1918, 0x1716, 0x1514, 0x1312,
            0x1110, 0x0f0e, 0x0d0c, 0x0b0a,
        )),
        addr
    );

1.9.0 (const: unstable) · Source§

### impl From<[u8; 16]> for Ipv6Addr

Source§

#### fn from(octets: [u8; 16]) -> Ipv6Addr

Creates an `Ipv6Addr` from a sixteen element byte array.

##### §Examples

    use std::net::Ipv6Addr;

    let addr = Ipv6Addr::from([
        0x19u8, 0x18u8, 0x17u8, 0x16u8, 0x15u8, 0x14u8, 0x13u8, 0x12u8,
        0x11u8, 0x10u8, 0x0fu8, 0x0eu8, 0x0du8, 0x0cu8, 0x0bu8, 0x0au8,
    ]);
    assert_eq!(
        Ipv6Addr::new(
            0x1918, 0x1716, 0x1514, 0x1312,
            0x1110, 0x0f0e, 0x0d0c, 0x0b0a,
        ),
        addr
    );

1.17.0 (const: unstable) · Source§

### impl From<[u8; 4]> for IpAddr

Source§

#### fn from(octets: [u8; 4]) -> IpAddr

Creates an `IpAddr::V4` from a four element byte array.

##### §Examples

    use std::net::{IpAddr, Ipv4Addr};

    let addr = IpAddr::from([13u8, 12u8, 11u8, 10u8]);
    assert_eq!(IpAddr::V4(Ipv4Addr::new(13, 12, 11, 10)), addr);

1.9.0 (const: unstable) · Source§

### impl From<[u8; 4]> for Ipv4Addr

Source§

#### fn from(octets: [u8; 4]) -> Ipv4Addr

Creates an `Ipv4Addr` from a four element byte array.

##### §Examples

    use std::net::Ipv4Addr;

    let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
    assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);

1.71.0 · Source§

### impl<T> From<(T₁, T₂, …, Tₙ)> for [T; N]

This trait is implemented for tuples up to twelve items long.

Source§

#### fn from(tuple: (T,)) -> Self

Converts to this type from the input type.
Source§

### impl<T, const N: usize> From<Mask<T, N>> for [bool; N]
where T: MaskElement, LaneCount<N>: SupportedLaneCount,

Source§

#### fn from(vector: Mask<T, N>) -> Self

Converts to this type from the input type.
Source§

### impl<T, const N: usize> From<Simd<T, N>> for [T; N]
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### fn from(vector: Simd<T, N>) -> Self

Converts to this type from the input type.
1.0.0 · Source§

### impl<T: Hash, const N: usize> Hash for [T; N]

The hash of an array is the same as that of the corresponding slice, as required by the `Borrow` implementation.

    use std::hash::BuildHasher;

    let b = std::hash::RandomState::new();
    let a: [u8; 3] = [0xa8, 0x3c, 0x09];
    let s: &[u8] = &[0xa8, 0x3c, 0x09];
    assert_eq!(b.hash_one(a), b.hash_one(s));

Source§

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

Feeds this value into the given `Hasher`. Read more
1.3.0 · Source§

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

Feeds a slice of this type into the given `Hasher`. Read more
1.50.0 (const: unstable) · Source§

### impl<T, I, const N: usize> Index<I> for [T; N]
where [T]: Index<I>,

Source§

#### type Output = <[T] as Index<I>>::Output

The returned type after indexing.
Source§

#### fn index(&self, index: I) -> &Self::Output

Performs the indexing (`container[index]`) operation. Read more
1.50.0 (const: unstable) · Source§

### impl<T, I, const N: usize> IndexMut<I> for [T; N]
where [T]: IndexMut<I>,

Source§

#### fn index_mut(&mut self, index: I) -> &mut Self::Output

Performs the mutable indexing (`container[index]`) operation. Read more
1.0.0 · Source§

### impl<'a, T, const N: usize> IntoIterator for &'a [T; N]

Source§

#### type Item = &'a T

The type of the elements being iterated over.
Source§

#### type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?
Source§

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

Creates an iterator from a value. Read more
1.0.0 · Source§

### impl<'a, T, const N: usize> IntoIterator for &'a mut [T; N]

Source§

#### type Item = &'a mut T

The type of the elements being iterated over.
Source§

#### type IntoIter = IterMut<'a, T>

Which kind of iterator are we turning this into?
Source§

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

Creates an iterator from a value. Read more
1.53.0 · Source§

### impl<T, const N: usize> IntoIterator for [T; N]

Source§

#### fn into_iter(self) -> Self::IntoIter

Creates a consuming iterator, that is, one that moves each value out of the array (from start to end).

The array cannot be used after calling this unless `T` implements `Copy`, so the whole array is copied.

Arrays have special behavior when calling `.into_iter()` prior to the 2021 edition – see the array Editions section for more information.

Source§

#### type Item = T

The type of the elements being iterated over.
Source§

#### type IntoIter = IntoIter<T, N>

Which kind of iterator are we turning this into?
1.0.0 · Source§

### impl<T: Ord, const N: usize> Ord for [T; N]

Implements comparison of arrays lexicographically.

Source§

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

This method returns an `Ordering` between `self` and `other`. Read more
1.21.0 · Source§

#### fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · Source§

#### fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · Source§

#### fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized,

Restrict a value to a certain interval. Read more
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<&[U]> for [T; N]
where T: PartialEq<U>,

Source§

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

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<const N: usize> PartialEq<&[u8; N]> for ByteStr

Source§

#### fn eq(&self, other: &&[u8; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<&mut [U]> for [T; N]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &&mut [U]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &&mut [U]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<[U]> for [T; N]
where T: PartialEq<U>,

Source§

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

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for &[T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for &mut [T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for [T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 (const: unstable) · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for [T; N]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<const N: usize> PartialEq<[u8; N]> for ByteStr

Source§

#### fn eq(&self, other: &[u8; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<const N: usize> PartialEq<ByteStr> for &[u8; N]

Source§

#### fn eq(&self, other: &ByteStr) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<const N: usize> PartialEq<ByteStr> for [u8; N]

Source§

#### fn eq(&self, other: &ByteStr) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

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

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T: PartialOrd, const N: usize> PartialOrd for [T; N]

Implements comparison of arrays lexicographically.

Source§

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

This method returns an ordering between `self` and `other` values if one exists. Read more
Source§

#### fn lt(&self, other: &[T; N]) -> bool

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
Source§

#### fn le(&self, other: &[T; N]) -> bool

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
Source§

#### fn ge(&self, other: &[T; N]) -> bool

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
Source§

#### fn gt(&self, other: &[T; N]) -> bool

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
Source§

### impl<'b, const N: usize> Pattern for &'b [char; N]

Searches for chars that are equal to any of the `char`s in the array.

#### §Examples

    assert_eq!("Hello world".find(&['o', 'l']), Some(2));
    assert_eq!("Hello world".find(&['h', 'w']), Some(6));

Source§

#### type Searcher<'a> = CharArrayRefSearcher<'a, 'b, N>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Associated searcher for this pattern
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Constructs the associated searcher from `self` and the `haystack` to search in.
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches anywhere in the haystack
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the front of the haystack
Source§

#### fn strip_prefix_of<'a>(self, haystack: &'a str) -> Option<&'a str>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the front of haystack, if it matches.
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the back of the haystack
Source§

#### fn strip_suffix_of<'a>(self, haystack: &'a str) -> Option<&'a str>
where CharArrayRefSearcher<'a, 'b, N>: ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the back of haystack, if it matches.
Source§

#### fn as_utf8_pattern(&self) -> Option<Utf8Pattern<'_>>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Returns the pattern as utf-8 bytes if possible.
Source§

### impl<const N: usize> Pattern for [char; N]

Searches for chars that are equal to any of the `char`s in the array.

#### §Examples

    assert_eq!("Hello world".find(['o', 'l']), Some(2));
    assert_eq!("Hello world".find(['h', 'w']), Some(6));

Source§

#### type Searcher<'a> = CharArraySearcher<'a, N>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Associated searcher for this pattern
Source§

#### fn into_searcher<'a>(self, haystack: &'a str) -> CharArraySearcher<'a, N>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Constructs the associated searcher from `self` and the `haystack` to search in.
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches anywhere in the haystack
Source§

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

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the front of the haystack
Source§

#### fn strip_prefix_of<'a>(self, haystack: &'a str) -> Option<&'a str>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the front of haystack, if it matches.
Source§

#### fn is_suffix_of<'a>(self, haystack: &'a str) -> bool
where CharArraySearcher<'a, N>: ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the back of the haystack
Source§

#### fn strip_suffix_of<'a>(self, haystack: &'a str) -> Option<&'a str>
where CharArraySearcher<'a, N>: ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the back of haystack, if it matches.
Source§

#### fn as_utf8_pattern(&self) -> Option<Utf8Pattern<'_>>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Returns the pattern as utf-8 bytes if possible.
1.51.0 · Source§

### impl<T, const N: usize> SlicePattern for [T; N]

Source§

#### type Item = T

🔬This is a nightly-only experimental API. (`slice_pattern` #56345)
The element type of the slice being matched on.
Source§

#### fn as_slice(&self) -> &[Self::Item]

🔬This is a nightly-only experimental API. (`slice_pattern` #56345)
Currently, the consumers of `SlicePattern` need a slice.
1.34.0 (const: unstable) · Source§

### impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N]

Tries to create an array ref `&[T; N]` from a slice ref `&[T]`. Succeeds if `slice.len() == N`.

    let bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: &[u8; 2] = <&[u8; 2]>::try_from(&bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(*bytes_head));

    let bytes_tail: &[u8; 2] = bytes[1..3].try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(*bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &'a [T]) -> Result<&'a [T; N], TryFromSliceError>

Performs the conversion.
1.34.0 (const: unstable) · Source§

### impl<T, const N: usize> TryFrom<&[T]> for [T; N]
where T: Copy,

Tries to create an array `[T; N]` by copying from a slice `&[T]`. Succeeds if `slice.len() == N`.

    let bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(bytes_head));

    let bytes_tail: [u8; 2] = bytes[1..3].try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &[T]) -> Result<[T; N], TryFromSliceError>

Performs the conversion.
1.34.0 (const: unstable) · Source§

### impl<'a, T, const N: usize> TryFrom<&'a mut [T]> for &'a mut [T; N]

Tries to create a mutable array ref `&mut [T; N]` from a mutable slice ref `&mut [T]`. Succeeds if `slice.len() == N`.

    let mut bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: &mut [u8; 2] = <&mut [u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(*bytes_head));

    let bytes_tail: &mut [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(*bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &'a mut [T]) -> Result<&'a mut [T; N], TryFromSliceError>

Performs the conversion.
1.59.0 (const: unstable) · Source§

### impl<T, const N: usize> TryFrom<&mut [T]> for [T; N]
where T: Copy,

Tries to create an array `[T; N]` by copying from a mutable slice `&mut [T]`. Succeeds if `slice.len() == N`.

    let mut bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(bytes_head));

    let bytes_tail: [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &mut [T]) -> Result<[T; N], TryFromSliceError>

Performs the conversion.
Source§

### impl<T: CloneFromCell, const N: usize> CloneFromCell for [T; N]

Source§

### impl<T: ConstParamTy_, const N: usize> ConstParamTy_ for [T; N]

1.58.0 · Source§

### impl<T: Copy, const N: usize> Copy for [T; N]

1.0.0 (const: unstable) · Source§

### impl<T: Eq, const N: usize> Eq for [T; N]

Source§

### impl<T, const N: usize> StructuralPartialEq for [T; N]

## Auto Trait Implementations§

§

### impl<T, const N: usize> Freeze for [MaybeUninit<T>; N]
where T: Freeze,

§

### impl<T, const N: usize> RefUnwindSafe for [MaybeUninit<T>; N]
where T: RefUnwindSafe,

§

### impl<T, const N: usize> Send for [MaybeUninit<T>; N]
where T: Send,

§

### impl<T, const N: usize> Sync for [MaybeUninit<T>; N]
where T: Sync,

§

### impl<T, const N: usize> Unpin for [MaybeUninit<T>; N]
where T: Unpin,

§

### impl<T, const N: usize> UnwindSafe for [MaybeUninit<T>; N]
where T: UnwindSafe,

## Blanket Implementations§

Source§

### impl<T> Any for T
where T: 'static + ?Sized,

Source§

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
Source§

### impl<T> Borrow<T> for T
where T: ?Sized,

Source§

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.