pub trait IntoIterator {
    type Item;
    type IntoIter: Iterator<Item = Self::Item>;

    // Required method
    fn into_iter(self) -> Self::IntoIter;
}
Available on non-crate feature miri-test-libstd only.
Expand description

Conversion into an Iterator.

By implementing IntoIterator for a type, you define how it will be converted to an iterator. This is common for types which describe a collection of some kind.

One benefit of implementing IntoIterator is that your type will work with Rust’s for loop syntax.

See also: FromIterator.

Examples

Basic usage:

let v = [1, 2, 3];
let mut iter = v.into_iter();

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

Implementing IntoIterator for your type:

// A sample collection, that's just a wrapper over Vec<T>
#[derive(Debug)]
struct MyCollection(Vec<i32>);

// Let's give it some methods so we can create one and add things
// to it.
impl MyCollection {
    fn new() -> MyCollection {
        MyCollection(Vec::new())
    }

    fn add(&mut self, elem: i32) {
        self.0.push(elem);
    }
}

// and we'll implement IntoIterator
impl IntoIterator for MyCollection {
    type Item = i32;
    type IntoIter = std::vec::IntoIter<Self::Item>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}

// Now we can make a new collection...
let mut c = MyCollection::new();

// ... add some stuff to it ...
c.add(0);
c.add(1);
c.add(2);

// ... and then turn it into an Iterator:
for (i, n) in c.into_iter().enumerate() {
    assert_eq!(i as i32, n);
}

It is common to use IntoIterator as a trait bound. This allows the input collection type to change, so long as it is still an iterator. Additional bounds can be specified by restricting on Item:

fn collect_as_strings<T>(collection: T) -> Vec<String>
where
    T: IntoIterator,
    T::Item: std::fmt::Debug,
{
    collection
        .into_iter()
        .map(|item| format!("{item:?}"))
        .collect()
}

Required Associated Types§

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type Item

The type of the elements being iterated over.

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type IntoIter: Iterator<Item = Self::Item>

Which kind of iterator are we turning this into?

Required Methods§

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fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

See the module-level documentation for more.

Examples

Basic usage:

let v = [1, 2, 3];
let mut iter = v.into_iter();

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

Implementors§

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impl IntoIterator for IndexVec

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impl IntoIterator for Bytes

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impl IntoIterator for BytesMut

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impl IntoIterator for PresentExtensions

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impl IntoIterator for MimeGuess

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type Item = Mime

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type IntoIter = Iter

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impl IntoIterator for WalkDir

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type Item = Result<DirEntry, Error>

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type IntoIter = IntoIter

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impl<'a> IntoIterator for &'a Bytes

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type Item = &'a u8

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type IntoIter = Iter<'a, u8>

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impl<'a> IntoIterator for &'a BytesMut

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type Item = &'a u8

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type IntoIter = Iter<'a, u8>

1.6.0 · source§

impl<'a> IntoIterator for &'a Path

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type Item = &'a OsStr

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type IntoIter = Iter<'a>

1.6.0 · source§

impl<'a> IntoIterator for &'a PathBuf

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type Item = &'a OsStr

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type IntoIter = Iter<'a>

1.10.0 · source§

impl<'a> IntoIterator for &'a UnixListener

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impl<'a> IntoIterator for &'a BorrowedCertRevocationList<'a>

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type Item = Result<BorrowedRevokedCert<'a>, Error>

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type IntoIter = RevokedCerts<'a>

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impl<'a> IntoIterator for &'a Events

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type Item = &'a Event

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type IntoIter = Iter<'a>

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impl<'a> IntoIterator for &'a FieldSet

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type IntoIter = Iter

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type Item = Field

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impl<'a> IntoIterator for &'a MimeGuess

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type Item = Mime

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type IntoIter = Iter

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impl<'a> IntoIterator for BerObject<'a>

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type Item = BerObject<'a>

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type IntoIter = BerObjectIntoIterator<'a>

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impl<'a, 'b, T> IntoIterator for &'b GetAll<'a, T>where 'b: 'a,

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type Item = &'a T

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type IntoIter = ValueIter<'a, T>

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impl<'a, 'b, T> IntoIterator for &'b OccupiedEntry<'a, T>where 'b: 'a,

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type Item = &'a T

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type IntoIter = ValueIter<'a, T>

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impl<'a, 'b, T> IntoIterator for &'b mut OccupiedEntry<'a, T>where 'b: 'a,

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impl<'a, A> IntoIterator for &'a ArrayVec<A>where A: Array,

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type Item = &'a <A as Array>::Item

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type IntoIter = Iter<'a, <A as Array>::Item>

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impl<'a, A> IntoIterator for &'a SmallVec<A>where A: Array,

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type IntoIter = Iter<'a, <A as Array>::Item>

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type Item = &'a <A as Array>::Item

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impl<'a, A> IntoIterator for &'a TinyVec<A>where A: Array,

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type Item = &'a <A as Array>::Item

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type IntoIter = Iter<'a, <A as Array>::Item>

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impl<'a, A> IntoIterator for &'a mut ArrayVec<A>where A: Array,

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type Item = &'a mut <A as Array>::Item

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type IntoIter = IterMut<'a, <A as Array>::Item>

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impl<'a, A> IntoIterator for &'a mut SmallVec<A>where A: Array,

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type IntoIter = IterMut<'a, <A as Array>::Item>

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type Item = &'a mut <A as Array>::Item

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impl<'a, A> IntoIterator for &'a mut TinyVec<A>where A: Array,

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type Item = &'a mut <A as Array>::Item

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type IntoIter = IterMut<'a, <A as Array>::Item>

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impl<'a, Fut> IntoIterator for &'a FuturesUnordered<Fut>where Fut: Unpin,

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type Item = &'a Fut

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type IntoIter = Iter<'a, Fut>

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impl<'a, Fut> IntoIterator for &'a mut FuturesUnordered<Fut>where Fut: Unpin,

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type Item = &'a mut Fut

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type IntoIter = IterMut<'a, Fut>

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impl<'a, K, V, A> IntoIterator for &'a BTreeMap<K, V, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, A> IntoIterator for &'a mut BTreeMap<K, V, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a mut V)

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type IntoIter = IterMut<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a kvarn::prelude::HashMap<K, V, S>

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type Item = (&'a K, &'a V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a IndexMap<K, V, S>

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type Item = (&'a K, &'a V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a Cache<K, V, S>where K: Hash + Eq + Send + Sync + 'static, V: Clone + Send + Sync + 'static, S: BuildHasher + Clone + Send + Sync + 'static,

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type Item = (Arc<K>, V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a DashMap<K, V, S>where K: Eq + Hash, S: BuildHasher + Clone,

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type Item = RefMulti<'a, K, V, S>

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type IntoIter = Iter<'a, K, V, S, DashMap<K, V, S>>

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impl<'a, K, V, S> IntoIterator for &'a SegmentedCache<K, V, S>where K: Hash + Eq + Send + Sync + 'static, V: Clone + Send + Sync + 'static, S: BuildHasher + Clone + Send + Sync + 'static,

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type Item = (Arc<K>, V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a mut kvarn::prelude::HashMap<K, V, S>

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type Item = (&'a K, &'a mut V)

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type IntoIter = IterMut<'a, K, V>

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impl<'a, K, V, S> IntoIterator for &'a mut IndexMap<K, V, S>

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type Item = (&'a K, &'a mut V)

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type IntoIter = IterMut<'a, K, V>

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impl<'a, K, V, S, A> IntoIterator for &'a HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S, A> IntoIterator for &'a HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a V)

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type IntoIter = Iter<'a, K, V>

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impl<'a, K, V, S, A> IntoIterator for &'a mut HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a mut V)

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type IntoIter = IterMut<'a, K, V>

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impl<'a, K, V, S, A> IntoIterator for &'a mut HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (&'a K, &'a mut V)

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type IntoIter = IterMut<'a, K, V>

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impl<'a, St> IntoIterator for &'a SelectAll<St>where St: Stream + Unpin,

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type Item = &'a St

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type IntoIter = Iter<'a, St>

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impl<'a, St> IntoIterator for &'a mut SelectAll<St>where St: Stream + Unpin,

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type Item = &'a mut St

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type IntoIter = IterMut<'a, St>

1.4.0 · source§

impl<'a, T> IntoIterator for &'a Option<T>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a [T]

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a HeaderMap<T>

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type Item = (&'a HeaderName, &'a T)

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a BinaryHeap<T>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a LinkedList<T>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

1.1.0 · source§

impl<'a, T> IntoIterator for &'a std::sync::mpsc::Receiver<T>

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type Item = T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a Receiver<T>

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type Item = T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a SequenceOf<T>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a SetOf<T>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T> IntoIterator for &'a Slab<T>

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type Item = (usize, &'a T)

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type IntoIter = Iter<'a, T>

1.4.0 · source§

impl<'a, T> IntoIterator for &'a mut Option<T>

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut [T]

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut HeaderMap<T>

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type Item = (&'a HeaderName, &'a mut T)

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut LinkedList<T>

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut SequenceOf<T>

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut SetOf<T>

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for &'a mut Slab<T>

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type Item = (usize, &'a mut T)

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type IntoIter = IterMut<'a, T>

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impl<'a, T> IntoIterator for GetAll<'a, T>

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type Item = &'a T

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type IntoIter = ValueIter<'a, T>

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impl<'a, T> IntoIterator for OccupiedEntry<'a, T>

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impl<'a, T, A> IntoIterator for &'a BTreeSet<T, A>where A: Allocator + Clone,

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, A> IntoIterator for &'a VecDeque<T, A>where A: Allocator,

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, A> IntoIterator for &'a Vec<T, A>where A: Allocator,

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, A> IntoIterator for &'a mut VecDeque<T, A>where A: Allocator,

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T, A> IntoIterator for &'a mut Vec<T, A>where A: Allocator,

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

1.4.0 · source§

impl<'a, T, E> IntoIterator for &'a Result<T, E>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

1.4.0 · source§

impl<'a, T, E> IntoIterator for &'a mut Result<T, E>

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'a, T, N> IntoIterator for &'a GenericArray<T, N>where T: 'a, N: ArrayLength<T>,

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type IntoIter = Iter<'a, T>

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type Item = &'a T

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impl<'a, T, N> IntoIterator for &'a mut GenericArray<T, N>where T: 'a, N: ArrayLength<T>,

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type IntoIter = IterMut<'a, T>

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type Item = &'a mut T

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impl<'a, T, S> IntoIterator for &'a std::collections::hash::set::HashSet<T, S>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, S> IntoIterator for &'a IndexSet<T, S>

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, S, A> IntoIterator for &'a HashSet<T, S, A>where A: Allocator + Clone,

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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impl<'a, T, S, A> IntoIterator for &'a HashSet<T, S, A>where A: Allocator + Clone,

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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

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type Item = &'a T

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type IntoIter = Iter<'a, T>

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

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type Item = &'a mut T

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type IntoIter = IterMut<'a, T>

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impl<'s, T> IntoIterator for SliceVec<'s, T>

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type Item = &'s mut T

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type IntoIter = IterMut<'s, T>

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impl<A> IntoIterator for ArrayVec<A>where A: Array,

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type Item = <A as Array>::Item

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type IntoIter = ArrayVecIterator<A>

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impl<A> IntoIterator for SmallVec<A>where A: Array,

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type IntoIter = IntoIter<A>

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type Item = <A as Array>::Item

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impl<A> IntoIterator for TinyVec<A>where A: Array,

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type Item = <A as Array>::Item

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type IntoIter = TinyVecIterator<A>

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impl<Fut> IntoIterator for FuturesUnordered<Fut>where Fut: Unpin,

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type Item = Fut

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type IntoIter = IntoIter<Fut>

const: unstable · source§

impl<I> IntoIterator for Iwhere I: Iterator,

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type Item = <I as Iterator>::Item

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type IntoIter = I

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impl<K, S> IntoIterator for DashSet<K, S>where K: Eq + Hash, S: BuildHasher + Clone,

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type Item = K

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type IntoIter = OwningIter<K, S>

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impl<K, V, A> IntoIterator for BTreeMap<K, V, A>where A: Allocator + Clone,

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type Item = (K, V)

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type IntoIter = IntoIter<K, V, A>

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impl<K, V, S> IntoIterator for kvarn::prelude::HashMap<K, V, S>

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type Item = (K, V)

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type IntoIter = IntoIter<K, V>

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impl<K, V, S> IntoIterator for IndexMap<K, V, S>

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type Item = (K, V)

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type IntoIter = IntoIter<K, V>

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impl<K, V, S> IntoIterator for DashMap<K, V, S>where K: Eq + Hash, S: BuildHasher + Clone,

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type Item = (K, V)

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type IntoIter = OwningIter<K, V, S>

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impl<K, V, S, A> IntoIterator for HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (K, V)

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type IntoIter = IntoIter<K, V, A>

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impl<K, V, S, A> IntoIterator for HashMap<K, V, S, A>where A: Allocator + Clone,

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type Item = (K, V)

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type IntoIter = IntoIter<K, V, A>

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impl<St> IntoIterator for SelectAll<St>where St: Stream + Unpin,

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type Item = St

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type IntoIter = IntoIter<St>

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impl<T> IntoIterator for Option<T>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T> IntoIterator for HeaderMap<T>

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impl<T> IntoIterator for BinaryHeap<T>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T> IntoIterator for LinkedList<T>

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type Item = T

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type IntoIter = IntoIter<T>

1.1.0 · source§

impl<T> IntoIterator for std::sync::mpsc::Receiver<T>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T> IntoIterator for Receiver<T>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T> IntoIterator for Slab<T>

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type Item = (usize, T)

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type IntoIter = IntoIter<T>

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impl<T, A> IntoIterator for BTreeSet<T, A>where A: Allocator + Clone,

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type Item = T

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type IntoIter = IntoIter<T, A>

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impl<T, A> IntoIterator for VecDeque<T, A>where A: Allocator,

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type Item = T

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type IntoIter = IntoIter<T, A>

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impl<T, A> IntoIterator for Vec<T, A>where A: Allocator,

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type Item = T

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type IntoIter = IntoIter<T, A>

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impl<T, A> IntoIterator for RawTable<T, A>where A: Allocator + Clone,

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type Item = T

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type IntoIter = RawIntoIter<T, A>

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impl<T, E> IntoIterator for Result<T, E>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T, N> IntoIterator for GenericArray<T, N>where N: ArrayLength<T>,

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type Item = T

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type IntoIter = GenericArrayIter<T, N>

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impl<T, S> IntoIterator for std::collections::hash::set::HashSet<T, S>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T, S> IntoIterator for IndexSet<T, S>

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type Item = T

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type IntoIter = IntoIter<T>

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impl<T, S, A> IntoIterator for HashSet<T, S, A>where A: Allocator + Clone,

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type Item = T

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type IntoIter = IntoIter<T, A>

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impl<T, S, A> IntoIterator for HashSet<T, S, A>where A: Allocator + Clone,

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type Item = T

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type IntoIter = IntoIter<T, A>

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impl<T, U> IntoIterator for Chain<T, U>where T: Buf, U: Buf,

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type Item = u8

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type IntoIter = IntoIter<Chain<T, U>>

1.53.0 · source§

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

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type Item = T

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type IntoIter = IntoIter<T, N>