Trait core::iter::IntoIterator [−] [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:

fn main() { 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); }
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:

fn main() { // 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); } }
// 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<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:

fn main() { 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); }
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