Trait std::iter::Extend
[−]
[src]
pub trait Extend<A> {
fn extend<T>(&mut self, iterable: T) where T: IntoIterator<Item=A>;
}
Extend a collection with the contents of an iterator.
Iterators produce a series of values, and collections can also be thought
of as a series of values. The Extend
trait bridges this gap, allowing you
to extend a collection by including the contents of that iterator.
Examples
Basic usage:
// You can extend a String with some chars: let mut message = String::from("The first three letters are: "); message.extend(&['a', 'b', 'c']); assert_eq!("abc", &message[29..32]);
Implementing Extend
:
// 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); } } // since MyCollection has a list of i32s, we implement Extend for i32 impl Extend<i32> for MyCollection { // This is a bit simpler with the concrete type signature: we can call // extend on anything which can be turned into an Iterator which gives // us i32s. Because we need i32s to put into MyCollection. fn extend<T: IntoIterator<Item=i32>>(&mut self, iterable: T) { // The implementation is very straightforward: loop through the // iterator, and add() each element to ourselves. for elem in iterable { self.add(elem); } } } let mut c = MyCollection::new(); c.add(5); c.add(6); c.add(7); // let's extend our collection with three more numbers c.extend(vec![1, 2, 3]); // we've added these elements onto the end assert_eq!("MyCollection([5, 6, 7, 1, 2, 3])", format!("{:?}", c));
Required Methods
fn extend<T>(&mut self, iterable: T) where T: IntoIterator<Item=A>
Extends a collection with the contents of an iterator.
As this is the only method for this trait, the trait-level docs contain more details.
Examples
Basic usage:
// You can extend a String with some chars: let mut message = String::from("abc"); message.extend(['d', 'e', 'f'].iter()); assert_eq!("abcdef", &message);
Implementors
impl<T> Extend<T> for BinaryHeap<T> where T: Ord
impl<'a, T> Extend<&'a T> for BinaryHeap<T> where T: Copy + 'a + Ord
impl<K, V> Extend<(K, V)> for BTreeMap<K, V> where K: Ord
impl<'a, K, V> Extend<(&'a K, &'a V)> for BTreeMap<K, V> where K: Copy + Ord, V: Copy
impl<T> Extend<T> for BTreeSet<T> where T: Ord
impl<'a, T> Extend<&'a T> for BTreeSet<T> where T: Copy + 'a + Ord
impl<E> Extend<E> for EnumSet<E> where E: CLike
impl<'a, E> Extend<&'a E> for EnumSet<E> where E: Copy + 'a + CLike
impl<A> Extend<A> for LinkedList<A>
impl<'a, T> Extend<&'a T> for LinkedList<T> where T: Copy + 'a
impl Extend<char> for String
impl<'a> Extend<&'a char> for String
impl<'a> Extend<&'a str> for String
impl Extend<String> for String
impl<T> Extend<T> for Vec<T>
impl<'a, T> Extend<&'a T> for Vec<T> where T: Copy + 'a
impl<A> Extend<A> for VecDeque<A>
impl<'a, T> Extend<&'a T> for VecDeque<T> where T: Copy + 'a
impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S> where K: Eq + Hash, S: HashState
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S> where K: Eq + Hash + Copy, V: Copy, S: HashState
impl<T, S> Extend<T> for HashSet<T, S> where T: Eq + Hash, S: HashState
impl<'a, T, S> Extend<&'a T> for HashSet<T, S> where T: 'a + Eq + Hash + Copy, S: HashState