Struct bevy::hierarchy::Children

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pub struct Children(/* private fields */);
Expand description

Contains references to the child entities of this entity.

Each child must contain a Parent component that points back to this entity. This component rarely needs to be created manually, consider using higher level utilities like BuildChildren::with_children which are safer and easier to use.

See HierarchyQueryExt for hierarchy related methods on Query.

Implementations§

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impl Children

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pub fn swap(&mut self, a_index: usize, b_index: usize)

Swaps the child at a_index with the child at b_index.

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

Sorts children stably in place using the provided comparator function.

For the underlying implementation, see slice::sort_by.

For the unstable version, see sort_unstable_by.

See also sort_by_key, sort_by_cached_key.

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

Sorts children stably in place using the provided key extraction function.

For the underlying implementation, see slice::sort_by_key.

For the unstable version, see sort_unstable_by_key.

See also sort_by, sort_by_cached_key.

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

Sorts children stably in place using the provided key extraction function. Only evaluates each key at most once per sort, caching the intermediate results in memory.

For the underlying implementation, see slice::sort_by_cached_key.

See also sort_by, sort_by_key.

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

Sorts children unstably in place using the provided comparator function.

For the underlying implementation, see slice::sort_unstable_by.

For the stable version, see sort_by.

See also sort_unstable_by_key.

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

Sorts children unstably in place using the provided key extraction function.

For the underlying implementation, see slice::sort_unstable_by_key.

For the stable version, see sort_by_key.

See also sort_unstable_by.

Methods from Deref<Target = [Entity]>§

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pub fn as_str(&self) -> &str

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

Views this slice of ASCII characters as a UTF-8 str.

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pub fn as_bytes(&self) -> &[u8]

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

Views this slice of ASCII characters as a slice of u8 bytes.

1.23.0 · source

pub fn is_ascii(&self) -> bool

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

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pub fn as_ascii(&self) -> Option<&[AsciiChar]>

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

If this slice is_ascii, returns it as a slice of ASCII characters, otherwise returns None.

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pub unsafe fn as_ascii_unchecked(&self) -> &[AsciiChar]

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

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

Safety

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

1.23.0 · source

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.

1.60.0 · source

pub fn escape_ascii(&self) -> EscapeAscii<'_>

Returns an iterator that produces an escaped version of this slice, treating it as an ASCII string.

Examples

let s = b"0\t\r\n'\"\\\x9d";
let escaped = s.escape_ascii().to_string();
assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");
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pub fn trim_ascii_start(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with leading ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b" \t hello world\n".trim_ascii_start(), b"hello world\n");
assert_eq!(b"  ".trim_ascii_start(), b"");
assert_eq!(b"".trim_ascii_start(), b"");
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pub fn trim_ascii_end(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b"\r hello world\n ".trim_ascii_end(), b"\r hello world");
assert_eq!(b"  ".trim_ascii_end(), b"");
assert_eq!(b"".trim_ascii_end(), b"");
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pub fn trim_ascii(&self) -> &[u8]

🔬This is a nightly-only experimental API. (byte_slice_trim_ascii)

Returns a byte slice with leading and trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples
#![feature(byte_slice_trim_ascii)]

assert_eq!(b"\r hello world\n ".trim_ascii(), b"hello world");
assert_eq!(b"  ".trim_ascii(), b"");
assert_eq!(b"".trim_ascii(), b"");
1.0.0 · source

pub fn len(&self) -> usize

Returns the number of elements in the slice.

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

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());
1.0.0 · source

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());
1.5.0 · source

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]);
}
1.5.0 · source

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]);
}
1.0.0 · source

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());
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pub fn first_chunk<const N: usize>(&self) -> Option<&[T; N]>

🔬This is a nightly-only experimental API. (slice_first_last_chunk)

Returns the first N elements of the slice, or None if it has fewer than N elements.

Examples
#![feature(slice_first_last_chunk)]

let u = [10, 40, 30];
assert_eq!(Some(&[10, 40]), u.first_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.first_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.first_chunk::<0>());
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pub fn split_first_chunk<const N: usize>(&self) -> Option<(&[T; N], &[T])>

🔬This is a nightly-only experimental API. (slice_first_last_chunk)

Returns the first N elements of the slice and the remainder, or None if it has fewer than N elements.

Examples
#![feature(slice_first_last_chunk)]

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

if let Some((first, elements)) = x.split_first_chunk::<2>() {
    assert_eq!(first, &[0, 1]);
    assert_eq!(elements, &[2]);
}
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pub fn split_last_chunk<const N: usize>(&self) -> Option<(&[T; N], &[T])>

🔬This is a nightly-only experimental API. (slice_first_last_chunk)

Returns the last N elements of the slice and the remainder, or None if it has fewer than N elements.

Examples
#![feature(slice_first_last_chunk)]

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

if let Some((last, elements)) = x.split_last_chunk::<2>() {
    assert_eq!(last, &[1, 2]);
    assert_eq!(elements, &[0]);
}
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pub fn last_chunk<const N: usize>(&self) -> Option<&[T; N]>

🔬This is a nightly-only experimental API. (slice_first_last_chunk)

Returns the last element of the slice, or None if it is empty.

Examples
#![feature(slice_first_last_chunk)]

let u = [10, 40, 30];
assert_eq!(Some(&[40, 30]), u.last_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.last_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.last_chunk::<0>());
1.0.0 · source

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));
1.0.0 · source

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.

For a safe alternative see get.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

You can think of this like .get(index).unwrap_unchecked(). It’s UB to call .get_unchecked(len), even if you immediately convert to a pointer. And it’s UB to call .get_unchecked(..len + 1), .get_unchecked(..=len), or similar.

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

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

pub 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.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

Examples
let x = &[1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
    }
}
1.48.0 · source

pub fn as_ptr_range(&self) -> Range<*const T>

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See as_ptr for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

let a = [1, 2, 3];
let x = &a[1] as *const _;
let y = &5 as *const _;

assert!(a.as_ptr_range().contains(&x));
assert!(!a.as_ptr_range().contains(&y));
1.0.0 · source

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the slice.

The iterator yields all items from start to end.

Examples
let x = &[1, 2, 4];
let mut iterator = x.iter();

assert_eq!(iterator.next(), Some(&1));
assert_eq!(iterator.next(), Some(&2));
assert_eq!(iterator.next(), Some(&4));
assert_eq!(iterator.next(), None);
1.0.0 · source

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 = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.windows(3);
assert_eq!(iter.next().unwrap(), &['l', 'o', 'r']);
assert_eq!(iter.next().unwrap(), &['o', 'r', 'e']);
assert_eq!(iter.next().unwrap(), &['r', 'e', 'm']);
assert!(iter.next().is_none());

If the slice is shorter than size:

let slice = ['f', 'o', 'o'];
let mut iter = slice.windows(4);
assert!(iter.next().is_none());

There’s no windows_mut, as that existing would let safe code violate the “only one &mut at a time to the same thing” rule. However, you can sometimes use Cell::as_slice_of_cells in conjunction with windows to accomplish something similar:

use std::cell::Cell;

let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
let slice = &mut array[..];
let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
for w in slice_of_cells.windows(3) {
    Cell::swap(&w[0], &w[2]);
}
assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);
1.0.0 · source

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.

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());
1.31.0 · source

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']);
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pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, assuming that there’s no remainder.

Safety

This may only be called when

  • The slice splits exactly into N-element chunks (aka self.len() % N == 0).
  • N != 0.
Examples
#![feature(slice_as_chunks)]
let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &[[char; 1]] =
    // SAFETY: 1-element chunks never have remainder
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &[[char; 3]] =
    // SAFETY: The slice length (6) is a multiple of 3
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);

// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed
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pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (chunks, remainder) = slice.as_chunks();
assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
assert_eq!(remainder, &['m']);

If you expect the slice to be an exact multiple, you can combine let-else with an empty slice pattern:

#![feature(slice_as_chunks)]
let slice = ['R', 'u', 's', 't'];
let (chunks, []) = slice.as_chunks::<2>() else {
    panic!("slice didn't have even length")
};
assert_eq!(chunks, &[['R', 'u'], ['s', 't']]);
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pub fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])

🔬This is a nightly-only experimental API. (slice_as_chunks)

Splits the slice into a slice of N-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than N.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(slice_as_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let (remainder, chunks) = slice.as_rchunks();
assert_eq!(remainder, &['l']);
assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);
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pub fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N>

🔬This is a nightly-only experimental API. (array_chunks)

Returns an iterator over N elements of the slice at a time, starting at the beginning of the slice.

The chunks are array references and do not overlap. If N does not divide the length of the slice, then the last up to N-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

This method is the const generic equivalent of chunks_exact.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(array_chunks)]
let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.array_chunks();
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), &['m']);
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pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>

🔬This is a nightly-only experimental API. (array_windows)

Returns an iterator over overlapping windows of N elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of windows.

If N is greater than the size of the slice, it will return no windows.

Panics

Panics if N is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

Examples
#![feature(array_windows)]
let slice = [0, 1, 2, 3];
let mut iter = slice.array_windows();
assert_eq!(iter.next().unwrap(), &[0, 1]);
assert_eq!(iter.next().unwrap(), &[1, 2]);
assert_eq!(iter.next().unwrap(), &[2, 3]);
assert!(iter.next().is_none());
1.31.0 · source

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());
1.31.0 · source

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 end of the slice.

The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of rchunks.

See rchunks for a variant of this iterator that also returns the remainder as a smaller chunk, and chunks_exact for the same iterator but starting at the beginning of the slice.

Panics

Panics if chunk_size is 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']);
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pub fn group_by<F>(&self, pred: F) -> GroupBy<'_, T, F>
where F: FnMut(&T, &T) -> bool,

🔬This is a nightly-only experimental API. (slice_group_by)

Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.

The predicate is called on two elements following themselves, it means the predicate is called on slice[0] and slice[1] then on slice[1] and slice[2] and so on.

Examples
#![feature(slice_group_by)]

let slice = &[1, 1, 1, 3, 3, 2, 2, 2];

let mut iter = slice.group_by(|a, b| a == b);

assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
assert_eq!(iter.next(), Some(&[3, 3][..]));
assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

#![feature(slice_group_by)]

let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];

let mut iter = slice.group_by(|a, b| a <= b);

assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
assert_eq!(iter.next(), None);
1.0.0 · source

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_eq!(left, []);
   assert_eq!(right, [1, 2, 3, 4, 5, 6]);
}

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

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

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

🔬This is a nightly-only experimental API. (slice_split_at_unchecked)

Divides one slice into two at an index, without doing bounds checking.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

For a safe alternative see split_at.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that 0 <= mid <= self.len().

Examples
#![feature(slice_split_at_unchecked)]

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

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

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

unsafe {
    let (left, right) = v.split_at_unchecked(6);
    assert_eq!(left, [1, 2, 3, 4, 5, 6]);
    assert_eq!(right, []);
}
source

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

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

Divides one slice into an array and a remainder slice at an index.

The array will contain all indices from [0, N) (excluding the index N itself) and the slice will contain all indices from [N, len) (excluding the index len itself).

Panics

Panics if N > len.

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 rsplit_array_ref<const N: usize>(&self) -> (&[T], &[T; N])

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

Divides one slice into an array and a remainder slice at an index from the end.

The slice will contain all indices from [0, len - N) (excluding the index len - N itself) and the array will contain all indices from [len - N, len) (excluding the index len itself).

Panics

Panics if N > len.

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]);
}
1.0.0 · source

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());
1.51.0 · source

pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F>
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred. The matched element is contained in the end of the previous subslice as a terminator.

Examples
let slice = [10, 40, 33, 20];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

let slice = [3, 10, 40, 33];
let mut iter = slice.split_inclusive(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[3]);
assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert!(iter.next().is_none());
1.27.0 · source

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);
1.0.0 · source

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:?}");
}
1.0.0 · source

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:?}");
}
source

pub fn split_once<F>(&self, pred: F) -> Option<(&[T], &[T])>
where F: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (slice_split_once)

Splits the slice on the first element that matches the specified predicate.

If any matching elements are resent in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns None.

Examples
#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.split_once(|&x| x == 2), Some((
    &[1][..],
    &[3, 2, 4][..]
)));
assert_eq!(s.split_once(|&x| x == 0), None);
source

pub fn rsplit_once<F>(&self, pred: F) -> Option<(&[T], &[T])>
where F: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (slice_split_once)

Splits the slice on the last element that matches the specified predicate.

If any matching elements are resent in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns None.

Examples
#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.rsplit_once(|&x| x == 2), Some((
    &[1, 2, 3][..],
    &[4][..]
)));
assert_eq!(s.rsplit_once(|&x| x == 0), None);
1.0.0 · source

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

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

This operation is O(n).

Note that if you have a sorted slice, binary_search may be faster.

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

If you do not have a &T, but some other value that you can compare with one (for example, String implements PartialEq<str>), you can use iter().any:

let v = [String::from("hello"), String::from("world")]; // slice of `String`
assert!(v.iter().any(|e| e == "hello")); // search with `&str`
assert!(!v.iter().any(|e| e == "hi"));
1.0.0 · source

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

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(&[]));
1.0.0 · source

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

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(&[]));
1.51.0 · source

pub fn strip_prefix<P>(&self, prefix: &P) -> Option<&[T]>
where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

Returns a subslice with the prefix removed.

If the slice starts with prefix, returns the subslice after the prefix, wrapped in Some. If prefix is empty, simply returns the original slice.

If the slice does not start with prefix, returns None.

Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
assert_eq!(v.strip_prefix(&[50]), None);
assert_eq!(v.strip_prefix(&[10, 50]), None);

let prefix : &str = "he";
assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
           Some(b"llo".as_ref()));
1.51.0 · source

pub fn strip_suffix<P>(&self, suffix: &P) -> Option<&[T]>
where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

Returns a subslice with the suffix removed.

If the slice ends with suffix, returns the subslice before the suffix, wrapped in Some. If suffix is empty, simply returns the original slice.

If the slice does not end with suffix, returns None.

Examples
let v = &[10, 40, 30];
assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
assert_eq!(v.strip_suffix(&[50]), None);
assert_eq!(v.strip_suffix(&[50, 30]), None);

Binary searches this slice for a given element. If the slice is not sorted, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search_by, binary_search_by_key, and partition_point.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

assert_eq!(s.binary_search(&13),  Ok(9));
assert_eq!(s.binary_search(&4),   Err(7));
assert_eq!(s.binary_search(&100), Err(13));
let r = s.binary_search(&1);
assert!(match r { Ok(1..=4) => true, _ => false, });

If you want to find that whole range of matching items, rather than an arbitrary matching one, that can be done using partition_point:

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

let low = s.partition_point(|x| x < &1);
assert_eq!(low, 1);
let high = s.partition_point(|x| x <= &1);
assert_eq!(high, 5);
let r = s.binary_search(&1);
assert!((low..high).contains(&r.unwrap()));

assert!(s[..low].iter().all(|&x| x < 1));
assert!(s[low..high].iter().all(|&x| x == 1));
assert!(s[high..].iter().all(|&x| x > 1));

// For something not found, the "range" of equal items is empty
assert_eq!(s.partition_point(|x| x < &11), 9);
assert_eq!(s.partition_point(|x| x <= &11), 9);
assert_eq!(s.binary_search(&11), Err(9));

If you want to insert an item to a sorted vector, while maintaining sort order, consider using partition_point:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x < num);
// The above is equivalent to `let idx = s.binary_search(&num).unwrap_or_else(|x| x);`
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
1.0.0 · source

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

Binary searches this slice with a comparator function.

The comparator function should return an order code that indicates whether its argument is Less, Equal or Greater the desired target. If the slice is not sorted or if the comparator function does not implement an order consistent with the sort order of the underlying slice, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by_key, and partition_point.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

let seek = 13;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
let seek = 4;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
let seek = 100;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
let seek = 1;
let r = s.binary_search_by(|probe| probe.cmp(&seek));
assert!(match r { Ok(1..=4) => true, _ => false, });
1.10.0 · source

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

Binary searches this slice with a key extraction function.

Assumes that the slice is sorted by the key, for instance with sort_by_key using the same key extraction function. If the slice is not sorted by the key, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by, and partition_point.

Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
         (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
         (1, 21), (2, 34), (4, 55)];

assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
let r = s.binary_search_by_key(&1, |&(a, b)| b);
assert!(match r { Ok(1..=4) => true, _ => false, });
1.30.0 · source

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. How exactly the slice is split up is not specified; the middle part may be smaller than necessary. However, if this fails to return a maximal middle part, that is because code is running in a context where performance does not matter, such as a sanitizer attempting to find alignment bugs. Regular code running in a default (debug or release) execution will return a maximal middle part.

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);
}
source

pub fn as_simd<const LANES: usize>(&self) -> (&[T], &[Simd<T, LANES>], &[T])

🔬This is a nightly-only experimental API. (portable_simd)

Split a slice into a prefix, a middle of aligned SIMD types, and a suffix.

This is a safe wrapper around slice::align_to, so has the same weak postconditions as that method. You’re only assured that self.len() == prefix.len() + middle.len() * LANES + suffix.len().

Notably, all of the following are possible:

  • prefix.len() >= LANES.
  • middle.is_empty() despite self.len() >= 3 * LANES.
  • suffix.len() >= LANES.

That said, this is a safe method, so if you’re only writing safe code, then this can at most cause incorrect logic, not unsoundness.

Panics

This will panic if the size of the SIMD type is different from LANES times that of the scalar.

At the time of writing, the trait restrictions on Simd<T, LANES> keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like LANES == 3.

Examples
#![feature(portable_simd)]
use core::simd::prelude::*;

let short = &[1, 2, 3];
let (prefix, middle, suffix) = short.as_simd::<4>();
assert_eq!(middle, []); // Not enough elements for anything in the middle

// They might be split in any possible way between prefix and suffix
let it = prefix.iter().chain(suffix).copied();
assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);

fn basic_simd_sum(x: &[f32]) -> f32 {
    use std::ops::Add;
    let (prefix, middle, suffix) = x.as_simd();
    let sums = f32x4::from_array([
        prefix.iter().copied().sum(),
        0.0,
        0.0,
        suffix.iter().copied().sum(),
    ]);
    let sums = middle.iter().copied().fold(sums, f32x4::add);
    sums.reduce_sum()
}

let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);
source

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

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

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, f32::NAN].is_sorted());
source

pub fn is_sorted_by<'a, F>(&'a self, compare: F) -> bool
where F: FnMut(&'a T, &'a T) -> Option<Ordering>,

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

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.

source

pub fn is_sorted_by_key<'a, F, K>(&'a self, f: F) -> bool
where F: FnMut(&'a T) -> K, K: PartialOrd,

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

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()));
1.52.0 · source

pub fn partition_point<P>(&self, pred: P) -> usize
where P: FnMut(&T) -> bool,

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

See also binary_search, binary_search_by, and binary_search_by_key.

Examples
let v = [1, 2, 3, 3, 5, 6, 7];
let i = v.partition_point(|&x| x < 5);

assert_eq!(i, 4);
assert!(v[..i].iter().all(|&x| x < 5));
assert!(v[i..].iter().all(|&x| !(x < 5)));

If all elements of the slice match the predicate, including if the slice is empty, then the length of the slice will be returned:

let a = [2, 4, 8];
assert_eq!(a.partition_point(|x| x < &100), a.len());
let a: [i32; 0] = [];
assert_eq!(a.partition_point(|x| x < &100), 0);

If you want to insert an item to a sorted vector, while maintaining sort order:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x < num);
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);
source

pub fn flatten(&self) -> &[T]

🔬This is a nightly-only experimental API. (slice_flatten)

Takes a &[[T; N]], and flattens it to a &[T].

Panics

This panics if the length of the resulting slice would overflow a usize.

This is only possible when flattening a slice of arrays of zero-sized types, and thus tends to be irrelevant in practice. If size_of::<T>() > 0, this will never panic.

Examples
#![feature(slice_flatten)]

assert_eq!([[1, 2, 3], [4, 5, 6]].flatten(), &[1, 2, 3, 4, 5, 6]);

assert_eq!(
    [[1, 2, 3], [4, 5, 6]].flatten(),
    [[1, 2], [3, 4], [5, 6]].flatten(),
);

let slice_of_empty_arrays: &[[i32; 0]] = &[[], [], [], [], []];
assert!(slice_of_empty_arrays.flatten().is_empty());

let empty_slice_of_arrays: &[[u32; 10]] = &[];
assert!(empty_slice_of_arrays.flatten().is_empty());
1.0.0 · source

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.
source

pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A>
where A: Allocator, T: Clone,

🔬This is a nightly-only experimental API. (allocator_api)

Copies self into a new Vec with an allocator.

Examples
#![feature(allocator_api)]

use std::alloc::System;

let s = [10, 40, 30];
let x = s.to_vec_in(System);
// Here, `s` and `x` can be modified independently.
1.40.0 · source

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

Creates a vector by copying a slice n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);

A panic upon overflow:

// this will panic at runtime
b"0123456789abcdef".repeat(usize::MAX);
1.0.0 · source

pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Output
where [T]: Concat<Item>, Item: ?Sized,

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

Examples
assert_eq!(["hello", "world"].concat(), "helloworld");
assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
1.3.0 · source

pub fn join<Separator>( &self, sep: Separator ) -> <[T] as Join<Separator>>::Output
where [T]: Join<Separator>,

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

Examples
assert_eq!(["hello", "world"].join(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
1.0.0 · source

pub fn connect<Separator>( &self, sep: Separator ) -> <[T] as Join<Separator>>::Output
where [T]: Join<Separator>,

👎Deprecated since 1.3.0: renamed to join

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

Examples
assert_eq!(["hello", "world"].connect(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
1.23.0 · source

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.

1.23.0 · source

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§

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impl Component for Children
where Children: Send + Sync + 'static,

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type Storage = TableStorage

A marker type indicating the storage type used for this component. This must be either TableStorage or SparseStorage.
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impl Debug for Children

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

Formats the value using the given formatter. Read more
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impl Deref for Children

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type Target = [Entity]

The resulting type after dereferencing.
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fn deref(&self) -> &<Children as Deref>::Target

Dereferences the value.
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impl FromReflect for Children

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fn from_reflect(reflect: &(dyn Reflect + 'static)) -> Option<Children>

Constructs a concrete instance of Self from a reflected value.
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fn take_from_reflect( reflect: Box<dyn Reflect> ) -> Result<Self, Box<dyn Reflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails. Read more
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impl FromWorld for Children

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fn from_world(_world: &mut World) -> Children

Creates Self using data from the given World.
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impl GetTypeRegistration for Children

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impl<'a> IntoIterator for &'a Children

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type Item = <<&'a Children as IntoIterator>::IntoIter as Iterator>::Item

The type of the elements being iterated over.
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type IntoIter = Iter<'a, Entity>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> <&'a Children as IntoIterator>::IntoIter

Creates an iterator from a value. Read more
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impl MapEntities for Children

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fn map_entities<M>(&mut self, entity_mapper: &mut M)
where M: EntityMapper,

Updates all Entity references stored inside using entity_mapper. Read more
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impl Reflect for Children

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fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value. Read more
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fn into_any(self: Box<Children>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.
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fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any.
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fn into_reflect(self: Box<Children>) -> Box<dyn Reflect>

Casts this type to a boxed reflected value.
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fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a reflected value.
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fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable reflected value.
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fn clone_value(&self) -> Box<dyn Reflect>

Clones the value as a Reflect trait object. Read more
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fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value. Read more
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fn apply(&mut self, value: &(dyn Reflect + 'static))

Applies a reflected value to this value. Read more
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fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type. Read more
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fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type. Read more
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fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type. Read more
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fn reflect_owned(self: Box<Children>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type. Read more
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fn reflect_partial_eq(&self, value: &(dyn Reflect + 'static)) -> Option<bool>

Returns a “partial equality” comparison result. Read more
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fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type). Read more
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fn debug(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Debug formatter for the value. Read more
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fn serializable(&self) -> Option<Serializable<'_>>

Returns a serializable version of the value. Read more
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fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type. Read more
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impl TupleStruct for Children

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fn field(&self, index: usize) -> Option<&(dyn Reflect + 'static)>

Returns a reference to the value of the field with index index as a &dyn Reflect.
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fn field_mut(&mut self, index: usize) -> Option<&mut (dyn Reflect + 'static)>

Returns a mutable reference to the value of the field with index index as a &mut dyn Reflect.
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fn field_len(&self) -> usize

Returns the number of fields in the tuple struct.
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fn iter_fields(&self) -> TupleStructFieldIter<'_>

Returns an iterator over the values of the tuple struct’s fields.
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fn clone_dynamic(&self) -> DynamicTupleStruct

Clones the struct into a DynamicTupleStruct.
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impl TypePath for Children
where Children: Any + Send + Sync,

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fn type_path() -> &'static str

Returns the fully qualified path of the underlying type. Read more
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fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type. Read more
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fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous. Read more
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fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous. Read more
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fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous. Read more
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impl Typed for Children

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fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

Auto Trait Implementations§

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T, U> AsBindGroupShaderType<U> for T
where U: ShaderType, &'a T: for<'a> Into<U>,

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fn as_bind_group_shader_type(&self, _images: &RenderAssets<Image>) -> U

Return the T ShaderType for self. When used in AsBindGroup derives, it is safe to assume that all images in self exist.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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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<C> Bundle for C
where C: Component,

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fn component_ids( components: &mut Components, storages: &mut Storages, ids: &mut impl FnMut(ComponentId) )

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unsafe fn from_components<T, F>(ctx: &mut T, func: &mut F) -> C
where F: for<'a> FnMut(&'a mut T) -> OwningPtr<'a>,

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impl<T> Downcast<T> for T

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fn downcast(&self) -> &T

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impl<T> Downcast for T
where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
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impl<T> DowncastSync for T
where T: Any + Send + Sync,

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fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
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impl<C> DynamicBundle for C
where C: Component,

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fn get_components(self, func: &mut impl FnMut(StorageType, OwningPtr<'_>))

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impl<T> DynamicTypePath for T
where T: TypePath,

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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<S> FromSample<S> for S

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fn from_sample_(s: S) -> S

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impl<T> GetPath for T
where T: Reflect + ?Sized,

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fn reflect_path<'p>( &self, path: impl ReflectPath<'p> ) -> Result<&(dyn Reflect + 'static), ReflectPathError<'p>>

Returns a reference to the value specified by path. Read more
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fn reflect_path_mut<'p>( &mut self, path: impl ReflectPath<'p> ) -> Result<&mut (dyn Reflect + 'static), ReflectPathError<'p>>

Returns a mutable reference to the value specified by path. Read more
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fn path<'p, T>( &self, path: impl ReflectPath<'p> ) -> Result<&T, ReflectPathError<'p>>
where T: Reflect,

Returns a statically typed reference to the value specified by path. Read more
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fn path_mut<'p, T>( &mut self, path: impl ReflectPath<'p> ) -> Result<&mut T, ReflectPathError<'p>>
where T: Reflect,

Returns a statically typed mutable reference to the value specified by path. Read more
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impl<S> GetTupleStructField for S
where S: TupleStruct,

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fn get_field<T>(&self, index: usize) -> Option<&T>
where T: Reflect,

Returns a reference to the value of the field with index index, downcast to T.
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fn get_field_mut<T>(&mut self, index: usize) -> Option<&mut T>
where T: Reflect,

Returns a mutable reference to the value of the field with index index, downcast to T.
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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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> ToSample<U> for T
where U: FromSample<T>,

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fn to_sample_(self) -> U

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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.
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impl<T> Upcast<T> for T

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fn upcast(&self) -> Option<&T>

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<S, T> Duplex<S> for T
where T: FromSample<S> + ToSample<S>,

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impl<T> Settings for T
where T: 'static + Send + Sync,

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impl<T> WasmNotSend for T
where T: Send,

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impl<T> WasmNotSendSync for T

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impl<T> WasmNotSync for T
where T: Sync,