Trait IntoIterator

1.0.0 · Source

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

    // Required method
    fn into_iter(self) -> Self::IntoIter;
}

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.

§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§

1.0.0 · Source

type Item

The type of the elements being iterated over.

1.0.0 · Source

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

Which kind of iterator are we turning this into?

Required Methods§

1.0.0 · Source

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

See the module-level documentation for more.

§Examples

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());

IntoIterator

Trait IntoIterator Copy item path

§Examples

Required Associated Types§

type Item

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

Required Methods§

fn into_iter(self) -> Self::IntoIter

§Examples

Implementors§

impl IntoIterator for IndexVec

type Item = usize

type IntoIter = IndexVecIntoIter

impl IntoIterator for Bytes

type Item = u8

type IntoIter = IntoIter<Bytes>

impl IntoIterator for BytesMut

type Item = u8

type IntoIter = IntoIter<BytesMut>

impl IntoIterator for regex::re_set::bytes::SetMatches

type IntoIter = SetMatchesIntoIter

type Item = usize

impl IntoIterator for regex::re_set::unicode::SetMatches

type IntoIter = SetMatchesIntoIter

type Item = usize

impl IntoIterator for Map<String, Value>

type Item = (String, Value)

type IntoIter = IntoIter

impl<'a> IntoIterator for &'a Utf8Sequence

type IntoIter = Iter<'a, Utf8Range>

type Item = &'a Utf8Range

impl<'a> IntoIterator for &'a UnixListener

type Item = Result<UnixStream, Error>

type IntoIter = Incoming<'a>

impl<'a> IntoIterator for &'a Path

type Item = &'a OsStr

type IntoIter = Iter<'a>

impl<'a> IntoIterator for &'a PathBuf

type Item = &'a OsStr

type IntoIter = Iter<'a>

impl<'a> IntoIterator for &'a Bytes

type Item = &'a u8

type IntoIter = Iter<'a, u8>

impl<'a> IntoIterator for &'a BytesMut

type Item = &'a u8

type IntoIter = Iter<'a, u8>

impl<'a> IntoIterator for &'a regex::re_set::bytes::SetMatches

type IntoIter = SetMatchesIter<'a>

type Item = usize

impl<'a> IntoIterator for &'a regex::re_set::unicode::SetMatches

type IntoIter = SetMatchesIter<'a>

type Item = usize

impl<'a> IntoIterator for &'a Map<String, Value>

type Item = (&'a String, &'a Value)

type IntoIter = Iter<'a>

impl<'a> IntoIterator for &'a mut Map<String, Value>

type Item = (&'a String, &'a mut Value)

type IntoIter = IterMut<'a>

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

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

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

impl<'a, A> IntoIterator for &'a OrdSet<A>where A: 'a + Ord,

type Item = &'a A

type IntoIter = Iter<'a, A>

impl<'a, A> IntoIterator for &'a Vector<A>where A: Clone,

type Item = &'a A

type IntoIter = Iter<'a, A>

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

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

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

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

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

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

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

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

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

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

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

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

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

Trait IntoIterator

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

impl<'a, A> IntoIterator for &'a OrdSet<A>
where A: 'a + Ord,

impl<'a, A> IntoIterator for &'a Vector<A>
where A: Clone,

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

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

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

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

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

impl<'a, A> IntoIterator for Focus<'a, A>
where A: Clone + 'a,

impl<'a, A> IntoIterator for FocusMut<'a, A>
where A: Clone + 'a,

impl<'a, A, N> IntoIterator for &'a Chunk<A, N>
where N: ChunkLength<A>,

impl<'a, A, N> IntoIterator for &'a mut Chunk<A, N>
where N: ChunkLength<A>,

impl<'a, A, S> IntoIterator for &'a im::hash::set::HashSet<A, S>
where A: Hash + Eq, S: BuildHasher,

impl<'a, E> IntoIterator for &'a mut SignalsInfo<E>
where E: Exfiltrator,

impl<'a, I> IntoIterator for &'a IntoChunks<I>
where I: Iterator, <I as Iterator>::Item: 'a,

impl<'a, I> IntoIterator for &'a RcIter<I>
where I: Iterator,

impl<'a, I, A> IntoIterator for &'a Box<[I], A>
where A: Allocator,

impl<'a, I, A> IntoIterator for &'a mut Box<[I], A>
where A: Allocator,

impl<'a, K, I, F> IntoIterator for &'a GroupBy<K, I, F>
where I: Iterator, <I as Iterator>::Item: 'a, F: FnMut(&<I as Iterator>::Item) -> K, K: PartialEq,

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

impl<'a, K, V> IntoIterator for &'a OrdMap<K, V>
where K: Ord,

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

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

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

impl<'a, K, V, S> IntoIterator for &'a im::hash::map::HashMap<K, V, S>
where K: Hash + Eq, S: BuildHasher,