Struct IntoIter

pub struct IntoIterusize> { /* private fields */ }

A by-value array iterator.

Implementations

implusize> IntoIter

pub fn new(array: [T; N]) -> IntoIter

👎Deprecated since 1.59.0: use IntoIterator::into_iter instead

Creates a new iterator over the given array.

pub const unsafe fn new_unchecked( buffer: [MaybeUninit; N], initialized: Range<usize>, ) -> IntoIter

🔬This is a nightly-only experimental API. (array_into_iter_constructors #91583)

Creates an iterator over the elements in a partially-initialized buffer.

If you have a fully-initialized array, then use IntoIterator. But this is useful for returning partial results from unsafe code.

Safety

• The buffer[initialized] elements must all be initialized.
• The range must be canonical, with initialized.start <= initialized.end.
• The range must be in-bounds for the buffer, with initialized.end <= N. (Like how indexing [0][100..100] fails despite the range being empty.)

It’s sound to have more elements initialized than mentioned, though that will most likely result in them being leaked.

Examples

#![feature(array_into_iter_constructors)]
#![feature(maybe_uninit_uninit_array_transpose)]
use std::array::IntoIter;
use std::mem::MaybeUninit;

fn next_chunkconst N: usize>(
    it: &mut impl Iterator,
) -> Result<[T; N], IntoIter> {
    let mut buffer = [const { MaybeUninit::uninit() }; N];
    let mut i = 0;
    while i < N {
        match it.next() {
            Some(x) => {
                buffer[i].write(x);
                i += 1;
            }
            None => {
                // SAFETY: We've initialized the first `i` items
                unsafe {
                    return Err(IntoIter::new_unchecked(buffer, 0..i));
                }
            }
        }
    }

    // SAFETY: We've initialized all N items
    unsafe { Ok(buffer.transpose().assume_init()) }
}

let r: [_; 4] = next_chunk(&mut (10..16)).unwrap();
assert_eq!(r, [10, 11, 12, 13]);
let r: IntoIter<_, 40> = next_chunk(&mut (10..16)).unwrap_err();
assert_eq!(r.collect::_>>(), vec![10, 11, 12, 13, 14, 15]);

pub const fn empty() -> IntoIter

🔬This is a nightly-only experimental API. (array_into_iter_constructors #91583)

Creates an iterator over T which returns no elements.

If you just need an empty iterator, then use iter::empty() instead. And if you need an empty array, use [].

But this is useful when you need an array::IntoIter specifically.

Examples

#![feature(array_into_iter_constructors)]
use std::array::IntoIter;

let empty = IntoIter::3>::empty();
assert_eq!(empty.len(), 0);
assert_eq!(empty.as_slice(), &[]);

let empty = IntoIter::200>::empty();
assert_eq!(empty.len(), 0);

[1, 2].into_iter() and [].into_iter() have different types

#![feature(array_into_iter_constructors)]
use std::array::IntoIter;

pub fn get_bytes(b: bool) -> IntoIter {
    if b {
        [1, 2, 3, 4].into_iter()
    } else {
        [].into_iter() // error[E0308]: mismatched types
    }
}

But using this method you can get an empty iterator of appropriate size:

#![feature(array_into_iter_constructors)]
use std::array::IntoIter;

pub fn get_bytes(b: bool) -> IntoIter4> {
    if b {
        [1, 2, 3, 4].into_iter()
    } else {
        IntoIter::empty()
    }
}

assert_eq!(get_bytes(true).collect::_>>(), vec![1, 2, 3, 4]);
assert_eq!(get_bytes(false).collect::_>>(), vec![]);

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

Returns an immutable slice of all elements that have not been yielded yet.

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

Returns a mutable slice of all elements that have not been yielded yet.

Trait Implementations

implusize> Clone for IntoIter

where T: Clone,

fn clone(&self) -> IntoIter

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

implusize> Debug for IntoIter

where T: Debug,

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

Formats the value using the given formatter.

implusize> DoubleEndedIterator for IntoIter

fn next_back(&mut self) -> Option<<IntoIter as Iterator>::Item>

Removes and returns an element from the end of the iterator.

fn rfold(self, init: Acc, rfold: Fold) -> Acc

where Fold: FnMut(Acc, <IntoIter as Iterator>::Item) -> Acc,

An iterator method that reduces the iterator’s elements to a single, final value, starting from the back.

fn advance_back_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by #77404)

Advances the iterator from the back by n elements.

fn nth_back(&mut self, n: usize) -> OptionItem>

Returns the nth element from the end of the iterator.

fn try_rfold(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try

,

This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator.

fn rfind

(&mut self, predicate: P) -> OptionItem>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator from the back that satisfies a predicate.

implusize> Drop for IntoIter

fn drop(&mut self)

Executes the destructor for this type.

implusize> ExactSizeIterator for IntoIter

fn len(&self) -> usize

Returns the exact remaining length of the iterator.

fn is_empty(&self) -> bool

🔬This is a nightly-only experimental API. (exact_size_is_empty #35428)

Returns true if the iterator is empty.

implusize> Iterator for IntoIter

type Item = T

The type of the elements being iterated over.

fn next(&mut self) -> Option<<IntoIter as Iterator>::Item>

Advances the iterator and returns the next value.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn fold(self, init: Acc, fold: Fold) -> Acc

where Fold: FnMut(Acc, <IntoIter as Iterator>::Item) -> Acc,

Folds every element into an accumulator by applying an operation, returning the final result.

fn count(self) -> usize

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<<IntoIter as Iterator>::Item>

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by #77404)

Advances the iterator by n elements.

fn next_chunkusize>( &mut self, ) -> Result<[Self::Item; N], IntoIterItem, N>>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk #98326)

Advances the iterator and returns an array containing the next N values.

fn nth(&mut self, n: usize) -> OptionItem>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy

where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain(self, other: U) -> ChainIntoIterator>::IntoIter>

where Self: Sized, U: IntoIteratorItem>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip(self, other: U) -> ZipIntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse(self, separator: Self::Item) -> Intersperse

where Self: Sized, Self::Item: Clone,

🔬This is a nightly-only experimental API. (iter_intersperse #79524)

Creates a new iterator which places a copy of separator between adjacent items of the original iterator.

fn intersperse_with(self, separator: G) -> IntersperseWith

where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse #79524)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

fn map(self, f: F) -> Map

where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter

(self, predicate: P) -> Filter

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map(self, f: F) -> FilterMap

where Self: Sized, F: FnMut(Self::Item) -> Option,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate

where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable

where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while

(self, predicate: P) -> SkipWhile

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while

(self, predicate: P) -> TakeWhile

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while(self, predicate: P) -> MapWhile

where Self: Sized, P: FnMut(Self::Item) -> Option,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip

where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take

where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan(self, initial_state: St, f: F) -> Scan

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map(self, f: F) -> FlatMap

where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure.

fn flatten(self) -> Flatten

where Self: Sized, Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn map_windowsusize>(self, f: F) -> MapWindows

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows #87155)

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse

where Self: Sized,

Creates an iterator which ends after the first None.

fn inspect(self, f: F) -> Inspect

where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Iterator.

fn collect(self) -> B

where B: FromIteratorItem>, Self: Sized,

Transforms an iterator into a collection.

fn try_collect( &mut self, ) -> <Item as Try>::Residual as Residual>::TryType

where Self: Sized, Self::Item: Try, Item as Try>::Residual: Residual, B: FromIterator<Item as Try>::Output>,

🔬This is a nightly-only experimental API. (iterator_try_collect #94047)

Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered.

fn collect_into(self, collection: &mut E) -> &mut E

where E: ExtendItem>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into #94780)

Collects all the items from an iterator into a collection.

fn partition(self, f: F) -> (B, B)

where Self: Sized, B: Default + ExtendItem>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn partition_in_place<'a, T, P>(self, predicate: P) -> usize

where T: 'a, Self: Sized + DoubleEndedIterator&'a mut T>, P: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (iter_partition_in_place #62543)

Reorders the elements of this iterator in-place according to the given predicate, such that all those that return true precede all those that return false. Returns the number of true elements found.

fn is_partitioned

(self, predicate: P) -> bool

where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned #62544)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try

,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each(&mut self, f: F) -> R

where Self: Sized, F: FnMut(Self::Item) -> R, R: Try

()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn reduce(self, f: F) -> OptionItem>

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <Try>::Residual as Residual<Option<Try>::Output>>>::TryType

where Self: Sized, R: Try

Item>, Try>::Residual: Residual<OptionItem>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce #87053)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find

(&mut self, predicate: P) -> OptionItem>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map(&mut self, f: F) -> Option

where Self: Sized, F: FnMut(Self::Item) -> Option,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <Try>::Residual as Residual<OptionItem>>>::TryType

where Self: Sized, R: Try

bool>, Try>::Residual: Residual<OptionItem>>,

🔬This is a nightly-only experimental API. (try_find #63178)

Applies function to the elements of iterator and returns the first true result or the first error.

fn position

(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn rposition

(&mut self, predicate: P) -> Option<usize>

where P: FnMut(Self::Item) -> bool, Self: Sized + ExactSizeIterator + DoubleEndedIterator,

Searches for an element in an iterator from the right, returning its index.

fn max(self) -> OptionItem>

where Self: Sized, Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> OptionItem>

where Self: Sized, Self::Item: Ord,

Returns the minimum element of an iterator.

fn max_by_key(self, f: F) -> OptionItem>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by(self, compare: F) -> OptionItem>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key(self, f: F) -> OptionItem>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by(self, compare: F) -> OptionItem>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn rev(self) -> Rev

where Self: Sized + DoubleEndedIterator,

Reverses an iterator’s direction.

fn unzip(self) -> (FromA, FromB)

where FromA: Default + Extend, FromB: Default + Extend, Self: Sized + Iterator(A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied

where T: 'a + Copy, Self: Sized + Iterator&'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned

where T: 'a + Clone, Self: Sized + Iterator&'a T>,

Creates an iterator which clones all of its elements.

fn cycle(self) -> Cycle

where Self: Sized + Clone,

Repeats an iterator endlessly.

fn array_chunksusize>(self) -> ArrayChunks

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks #100450)

Returns an iterator over N elements of the iterator at a time.

fn sum(self) -> S

where Self: Sized, S: SumItem>,

Sums the elements of an iterator.

fn product

(self) -> P

where Self: Sized, P: ProductItem>,

Iterates over the entire iterator, multiplying all the elements

fn cmp(self, other: I) -> Ordering

where I: IntoIteratorItem>, Self::Item: Ord, Self: Sized,

Lexicographically compares the elements of this Iterator with those of another.

fn cmp_by(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by #64295)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by(self, other: I, partial_cmp: F) -> Option<Ordering>

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by #64295)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by #64295)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted(self) -> bool

where Self: Sized, Self::Item: PartialOrd,

Checks if the elements of this iterator are sorted.

fn is_sorted_by(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

Checks if the elements of this iterator are sorted using the given key extraction function.

implusize> FusedIterator for IntoIter

implusize> TrustedLen for IntoIter