Trait std::iter::IntoIterator [−] [src]

pub trait IntoIterator where Self::IntoIter::Item == Self::Item {
    type Item;
    type IntoIter: Iterator;
    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);

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);
}

Associated Types

type Item

The type of the elements being iterated over.

type IntoIter: Iterator

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);

Implementors