Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://doc.rust-lang.org/nightly/std/primitive.array.html below:

array - Rust

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.

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

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

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

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) { }

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();

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.

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

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

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

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.

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

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

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+)

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

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

for item in IntoIterator::into_iter(array) {
    let x: i32 = item;
    println!("{x}");
}

for item in array {
    let x: i32 = item;
    println!("{x}");
}

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

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

#![feature(maybe_uninit_uninit_array_transpose)]

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

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

#![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");

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

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

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.

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.

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]);

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]>.

#![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));

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

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

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

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]);

assert_eq!(strings.len(), 3);

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

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]);

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 if M > N.

#![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, &[]);
}

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 if M > N.

#![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]);

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 if M > N.

#![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]);
}

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 if M > N.

#![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]);

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

#![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);

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

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

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

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

Creates a Borrowed variant of Cow from a reference to an array.

This conversion does not allocate or clone the data.

Allocates a Vec<T> and fills it by cloning s’s items.

assert_eq!(Vec::from(&[1, 2, 3]), vec![1, 2, 3]);

Allocates a Vec<T> and fills it by cloning s’s items.

assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);

Converts a [(K, V); N] into a BTreeMap<K, V>.

If any entries in the array have equal keys, all but one of the corresponding values will be dropped.

use std::collections::BTreeMap;

let map1 = BTreeMap::from([(1, 2), (3, 4)]);
let map2: BTreeMap<_, _> = [(1, 2), (3, 4)].into();
assert_eq!(map1, map2);

Converts a [(K, V); N] into a HashMap<K, V>.

If any entries in the array have equal keys, all but one of the corresponding values will be dropped.

use std::collections::HashMap;

let map1 = HashMap::from([(1, 2), (3, 4)]);
let map2: HashMap<_, _> = [(1, 2), (3, 4)].into();
assert_eq!(map1, map2);

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

Converts to this type from the input type.

Converts a [T; N] into an Arc<[T]>.

The conversion moves the array into a newly allocated Arc.

let original: [i32; 3] = [1, 2, 3];
let shared: Arc<[i32]> = Arc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);

Converts a [T; N] into a BTreeSet<T>.

If the array contains any equal values, all but one will be dropped.

use std::collections::BTreeSet;

let set1 = BTreeSet::from([1, 2, 3, 4]);
let set2: BTreeSet<_> = [1, 2, 3, 4].into();
assert_eq!(set1, set2);

use std::collections::BinaryHeap;

let mut h1 = BinaryHeap::from([1, 4, 2, 3]);
let mut h2: BinaryHeap<_> = [1, 4, 2, 3].into();
while let Some((a, b)) = h1.pop().zip(h2.pop()) {
    assert_eq!(a, b);
}

Converts a [T; N] into a Box<[T]>

This conversion moves the array to newly heap-allocated memory.

let boxed: Box<[u8]> = Box::from([4, 2]);
println!("{boxed:?}");

Converts a [T; N] into a HashSet<T>.

If the array contains any equal values, all but one will be dropped.

use std::collections::HashSet;

let set1 = HashSet::from([1, 2, 3, 4]);
let set2: HashSet<_> = [1, 2, 3, 4].into();
assert_eq!(set1, set2);

Converts a [T; N] into a LinkedList<T>.

use std::collections::LinkedList;

let list1 = LinkedList::from([1, 2, 3, 4]);
let list2: LinkedList<_> = [1, 2, 3, 4].into();
assert_eq!(list1, list2);

Converts a [T; N] into an Rc<[T]>.

The conversion moves the array into a newly allocated Rc.

let original: [i32; 3] = [1, 2, 3];
let shared: Rc<[i32]> = Rc::from(original);
assert_eq!(&[1, 2, 3], &shared[..]);

Converts to this type from the input type.

Allocates a Vec<T> and moves s’s items into it.

assert_eq!(Vec::from([1, 2, 3]), vec![1, 2, 3]);

Converts a [T; N] into a VecDeque<T>.

use std::collections::VecDeque;

let deq1 = VecDeque::from([1, 2, 3, 4]);
let deq2: VecDeque<_> = [1, 2, 3, 4].into();
assert_eq!(deq1, deq2);

Converts to this type from the input type.

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

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
);

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

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
);

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

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
);

Creates an Ipv6Addr from a sixteen element byte array.

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
);

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

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

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

Creates an Ipv4Addr from a four element byte array.

use std::net::Ipv4Addr;

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

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

Converts to this type from the input type.

Converts to this type from the input type.

Converts to this type from the input type.

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));

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

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.

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Implements comparison of arrays lexicographically.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Implements comparison of arrays lexicographically.

This method returns an ordering between

and

values if one exists.

Tests less than (for

and

) and is used by the

operator.

Tests less than or equal to (for

and

) and is used by the

operator.

Tests greater than or equal to (for

and

) and is used by the

operator.

Tests greater than (for

and

) and is used by the

operator.

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

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

Associated searcher for this pattern

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

Checks whether the pattern matches anywhere in the haystack

Checks whether the pattern matches at the front of the haystack

Removes the pattern from the front of haystack, if it matches.

Checks whether the pattern matches at the back of the haystack

Removes the pattern from the back of haystack, if it matches.

Returns the pattern as utf-8 bytes if possible.

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

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

Associated searcher for this pattern

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

Checks whether the pattern matches anywhere in the haystack

Checks whether the pattern matches at the front of the haystack

Removes the pattern from the front of haystack, if it matches.

Checks whether the pattern matches at the back of the haystack

Removes the pattern from the back of haystack, if it matches.

Returns the pattern as utf-8 bytes if possible.

The element type of the slice being matched on.

Currently, the consumers of SlicePattern need a slice.

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

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

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

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

The type returned in the event of a conversion error.

Performs the conversion.

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

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

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

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

The type returned in the event of a conversion error.

Performs the conversion.

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

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

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

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

The type returned in the event of a conversion error.

Performs the conversion.

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

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

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

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

The type returned in the event of a conversion error.

Performs the conversion.

Attempts to convert a Box<[T]> into a Box<[T; N]>.

The conversion occurs in-place and does not require a new memory allocation.

Returns the old Box<[T]> in the Err variant if boxed_slice.len() does not equal N.

The type returned in the event of a conversion error.

Attempts to convert a Vec<T> into a Box<[T; N]>.

Like Vec::into_boxed_slice, this is in-place if vec.capacity() == N, but will require a reallocation otherwise.

Returns the original Vec<T> in the Err variant if boxed_slice.len() does not equal N.

This can be used with vec! to create an array on the heap:

let state: Box<[f32; 100]> = vec![1.0; 100].try_into().unwrap();
assert_eq!(state.len(), 100);

The type returned in the event of a conversion error.

Gets the entire contents of the Vec<T> as an array, if its size exactly matches that of the requested array.

assert_eq!(vec![1, 2, 3].try_into(), Ok([1, 2, 3]));
assert_eq!(<Vec<i32>>::new().try_into(), Ok([]));

If the length doesn’t match, the input comes back in Err:

let r: Result<[i32; 4], _> = (0..10).collect::<Vec<_>>().try_into();
assert_eq!(r, Err(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));

If you’re fine with just getting a prefix of the Vec<T>, you can call .truncate(N) first.

let mut v = String::from("hello world").into_bytes();
v.sort();
v.truncate(2);
let [a, b]: [_; 2] = v.try_into().unwrap();
assert_eq!(a, b' ');
assert_eq!(b, b'd');

The type returned in the event of a conversion error.

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4