core::iter::IntoIterator - Rust
Description: API documentation for the Rust `IntoIterator` trait in crate `core`.
Keywords: rust, rustlang, rust-lang, IntoIterator

# Trait core::iter::IntoIterator 1.0.0 [−] [src]

    pub trait IntoIterator {
        type Item;
        type IntoIter: Iterator<Item=Self::Item>;
        fn into_iter(self) -> Self::IntoIter;
    }

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 = vec![1, 2, 3];

    let mut iter = v.into_iter();

    let n = iter.next();
    assert_eq!(Some(1), n);

    let n = iter.next();
    assert_eq!(Some(2), n);

    let n = iter.next();
    assert_eq!(Some(3), n);

    let n = iter.next();
    assert_eq!(None, n);Run

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<i32>;

        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);
    }Run

## Associated Types

### `type Item`

The type of the elements being iterated over.

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

Which kind of iterator are we turning this into?

## Required Methods

### `fn into_iter(self) -> Self::IntoIter`

Creates an iterator from a value.

See the module-level documentation for more.

# Examples

Basic usage:

    let v = vec![1, 2, 3];

    let mut iter = v.into_iter();

    let n = iter.next();
    assert_eq!(Some(1), n);

    let n = iter.next();
    assert_eq!(Some(2), n);

    let n = iter.next();
    assert_eq!(Some(3), n);

    let n = iter.next();
    assert_eq!(None, n);Run

## Implementors

- `impl<'a, T> IntoIterator for &'a [T; 0]`
- `impl<'a, T> IntoIterator for &'a mut [T; 0]`
- `impl<'a, T> IntoIterator for &'a [T; 1]`
- `impl<'a, T> IntoIterator for &'a mut [T; 1]`
- `impl<'a, T> IntoIterator for &'a [T; 2]`
- `impl<'a, T> IntoIterator for &'a mut [T; 2]`
- `impl<'a, T> IntoIterator for &'a [T; 3]`
- `impl<'a, T> IntoIterator for &'a mut [T; 3]`
- `impl<'a, T> IntoIterator for &'a [T; 4]`
- `impl<'a, T> IntoIterator for &'a mut [T; 4]`
- `impl<'a, T> IntoIterator for &'a [T; 5]`
- `impl<'a, T> IntoIterator for &'a mut [T; 5]`
- `impl<'a, T> IntoIterator for &'a [T; 6]`
- `impl<'a, T> IntoIterator for &'a mut [T; 6]`
- `impl<'a, T> IntoIterator for &'a [T; 7]`
- `impl<'a, T> IntoIterator for &'a mut [T; 7]`
- `impl<'a, T> IntoIterator for &'a [T; 8]`
- `impl<'a, T> IntoIterator for &'a mut [T; 8]`
- `impl<'a, T> IntoIterator for &'a [T; 9]`
- `impl<'a, T> IntoIterator for &'a mut [T; 9]`
- `impl<'a, T> IntoIterator for &'a [T; 10]`
- `impl<'a, T> IntoIterator for &'a mut [T; 10]`
- `impl<'a, T> IntoIterator for &'a [T; 11]`
- `impl<'a, T> IntoIterator for &'a mut [T; 11]`
- `impl<'a, T> IntoIterator for &'a [T; 12]`
- `impl<'a, T> IntoIterator for &'a mut [T; 12]`
- `impl<'a, T> IntoIterator for &'a [T; 13]`
- `impl<'a, T> IntoIterator for &'a mut [T; 13]`
- `impl<'a, T> IntoIterator for &'a [T; 14]`
- `impl<'a, T> IntoIterator for &'a mut [T; 14]`
- `impl<'a, T> IntoIterator for &'a [T; 15]`
- `impl<'a, T> IntoIterator for &'a mut [T; 15]`
- `impl<'a, T> IntoIterator for &'a [T; 16]`
- `impl<'a, T> IntoIterator for &'a mut [T; 16]`
- `impl<'a, T> IntoIterator for &'a [T; 17]`
- `impl<'a, T> IntoIterator for &'a mut [T; 17]`
- `impl<'a, T> IntoIterator for &'a [T; 18]`
- `impl<'a, T> IntoIterator for &'a mut [T; 18]`
- `impl<'a, T> IntoIterator for &'a [T; 19]`
- `impl<'a, T> IntoIterator for &'a mut [T; 19]`
- `impl<'a, T> IntoIterator for &'a [T; 20]`
- `impl<'a, T> IntoIterator for &'a mut [T; 20]`
- `impl<'a, T> IntoIterator for &'a [T; 21]`
- `impl<'a, T> IntoIterator for &'a mut [T; 21]`
- `impl<'a, T> IntoIterator for &'a [T; 22]`
- `impl<'a, T> IntoIterator for &'a mut [T; 22]`
- `impl<'a, T> IntoIterator for &'a [T; 23]`
- `impl<'a, T> IntoIterator for &'a mut [T; 23]`
- `impl<'a, T> IntoIterator for &'a [T; 24]`
- `impl<'a, T> IntoIterator for &'a mut [T; 24]`
- `impl<'a, T> IntoIterator for &'a [T; 25]`
- `impl<'a, T> IntoIterator for &'a mut [T; 25]`
- `impl<'a, T> IntoIterator for &'a [T; 26]`
- `impl<'a, T> IntoIterator for &'a mut [T; 26]`
- `impl<'a, T> IntoIterator for &'a [T; 27]`
- `impl<'a, T> IntoIterator for &'a mut [T; 27]`
- `impl<'a, T> IntoIterator for &'a [T; 28]`
- `impl<'a, T> IntoIterator for &'a mut [T; 28]`
- `impl<'a, T> IntoIterator for &'a [T; 29]`
- `impl<'a, T> IntoIterator for &'a mut [T; 29]`
- `impl<'a, T> IntoIterator for &'a [T; 30]`
- `impl<'a, T> IntoIterator for &'a mut [T; 30]`
- `impl<'a, T> IntoIterator for &'a [T; 31]`
- `impl<'a, T> IntoIterator for &'a mut [T; 31]`
- `impl<'a, T> IntoIterator for &'a [T; 32]`
- `impl<'a, T> IntoIterator for &'a mut [T; 32]`
- `impl<I: Iterator> IntoIterator for I`
- `impl<T> IntoIterator for Option<T>`
- `impl<'a, T> IntoIterator for &'a Option<T>`
- `impl<'a, T> IntoIterator for &'a mut Option<T>`
- `impl<T, E> IntoIterator for Result<T, E>`
- `impl<'a, T, E> IntoIterator for &'a Result<T, E>`
- `impl<'a, T, E> IntoIterator for &'a mut Result<T, E>`
- `impl<'a, T> IntoIterator for &'a [T]`
- `impl<'a, T> IntoIterator for &'a mut [T]`

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