1.0.0[−][src]Trait std::iter::Extend
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. When
extending a collection with an already existing key, that entry is updated
or, in the case of collections that permit multiple entries with equal
keys, that entry is inserted.
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]);Run
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, iter: T) { // The implementation is very straightforward: loop through the // iterator, and add() each element to ourselves. for elem in iter { 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));Run
Required methods
fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = A>,
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);Run
Implementations on Foreign Types
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S> where
K: Eq + Hash + Copy,
S: BuildHasher,
V: Copy,
K: Eq + Hash + Copy,
S: BuildHasher,
V: Copy,
impl<T, S> Extend<T> for HashSet<T, S> where
S: BuildHasher,
T: Eq + Hash,
S: BuildHasher,
T: Eq + Hash,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = T>,
I: IntoIterator<Item = T>,
impl<'a, T, S> Extend<&'a T> for HashSet<T, S> where
S: BuildHasher,
T: 'a + Eq + Hash + Copy,
S: BuildHasher,
T: 'a + Eq + Hash + Copy,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
I: IntoIterator<Item = &'a T>,
impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher,
K: Eq + Hash,
S: BuildHasher,
fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = (K, V)>,
T: IntoIterator<Item = (K, V)>,
Implementors
impl Extend<char> for String
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = char>,
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I: IntoIterator<Item = char>,
impl Extend<()> for ()
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fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = ()>,
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T: IntoIterator<Item = ()>,
impl Extend<String> for String
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = String>,
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I: IntoIterator<Item = String>,
impl<'a> Extend<&'a char> for String
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a char>,
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I: IntoIterator<Item = &'a char>,
impl<'a> Extend<&'a str> for String
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a str>,
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I: IntoIterator<Item = &'a str>,
impl<'a> Extend<Cow<'a, str>> for String
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = Cow<'a, str>>,
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I: IntoIterator<Item = Cow<'a, str>>,
impl<'a, K, V> Extend<(&'a K, &'a V)> for BTreeMap<K, V> where
K: Copy + Ord,
V: Copy,
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K: Copy + Ord,
V: Copy,
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for std::collections::HashMap<K, V, S> where
K: Eq + Hash + Copy,
V: Copy,
S: BuildHasher,
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K: Eq + Hash + Copy,
V: Copy,
S: BuildHasher,
impl<'a, T> Extend<&'a T> for BinaryHeap<T> where
T: 'a + Copy + Ord,
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T: 'a + Copy + Ord,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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I: IntoIterator<Item = &'a T>,
impl<'a, T> Extend<&'a T> for BTreeSet<T> where
T: 'a + Copy + Ord,
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T: 'a + Copy + Ord,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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I: IntoIterator<Item = &'a T>,
impl<'a, T> Extend<&'a T> for LinkedList<T> where
T: 'a + Copy,
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T: 'a + Copy,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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I: IntoIterator<Item = &'a T>,
impl<'a, T> Extend<&'a T> for VecDeque<T> where
T: 'a + Copy,
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T: 'a + Copy,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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I: IntoIterator<Item = &'a T>,
impl<'a, T> Extend<&'a T> for Vec<T> where
T: 'a + Copy,
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T: 'a + Copy,
Extend implementation that copies elements out of references before pushing them onto the Vec.
This implementation is specialized for slice iterators, where it uses copy_from_slice
to
append the entire slice at once.
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = &'a T>,
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I: IntoIterator<Item = &'a T>,
impl<'a, T, S> Extend<&'a T> for std::collections::HashSet<T, S> where
T: 'a + Eq + Hash + Copy,
S: BuildHasher,
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T: 'a + Eq + Hash + Copy,
S: BuildHasher,
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I)
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impl<A> Extend<A> for VecDeque<A>
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fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = A>,
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T: IntoIterator<Item = A>,
impl<K, V> Extend<(K, V)> for BTreeMap<K, V> where
K: Ord,
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K: Ord,
fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = (K, V)>,
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T: IntoIterator<Item = (K, V)>,
impl<K, V, S> Extend<(K, V)> for std::collections::HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher,
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K: Eq + Hash,
S: BuildHasher,
fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T)
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impl<P: AsRef<Path>> Extend<P> for PathBuf
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fn extend<I: IntoIterator<Item = P>>(&mut self, iter: I)
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impl<T> Extend<T> for BinaryHeap<T> where
T: Ord,
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T: Ord,
fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = T>,
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I: IntoIterator<Item = T>,
impl<T> Extend<T> for BTreeSet<T> where
T: Ord,
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T: Ord,
fn extend<Iter>(&mut self, iter: Iter) where
Iter: IntoIterator<Item = T>,
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Iter: IntoIterator<Item = T>,
impl<T> Extend<T> for LinkedList<T>
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = T>,
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I: IntoIterator<Item = T>,
impl<T> Extend<T> for Vec<T>
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fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = T>,
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I: IntoIterator<Item = T>,
impl<T, S> Extend<T> for std::collections::HashSet<T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,