Trait sp_std::iter::Extend

pub trait Extend<A> {
    fn extend<T>(&mut self, iter: T)
    where
        T: IntoIterator<Item = A>;

    fn extend_one(&mut self, item: A) { ... }
    fn extend_reserve(&mut self, additional: usize) { ... }
}

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]);

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));

Required methods

fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = A>, 

Extends a collection with the contents of an iterator.

As this is the only required 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);

Provided methods

fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

The default implementation does nothing.

Implementations on Foreign Types

impl<'a> Extend<Cow<'a, OsStr>> for OsString

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = Cow<'a, OsStr>>, 

impl<'a, T, S> Extend<&'a T> for HashSet<T, S> where
    T: 'a + Eq + Hash + Copy,
    S: BuildHasher, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a T>, 

pub fn extend_one(&mut self, &'a T)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S> where
    K: Eq + Hash,
    S: BuildHasher, 

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = (K, V)>, 

pub fn extend_one(&mut self, (K, V))

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<T, S> Extend<T> for HashSet<T, S> where
    T: Eq + Hash,
    S: BuildHasher, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = T>, 

pub fn extend_one(&mut self, item: T)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<P> Extend<P> for PathBuf where
    P: AsRef<Path>, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = P>, 

pub fn extend_one(&mut self, p: P)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a> Extend<&'a OsStr> for OsString

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = &'a OsStr>, 

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S> where
    K: Eq + Hash + Copy,
    V: Copy,
    S: BuildHasher, 

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = (&'a K, &'a V)>, 

pub fn extend_one(&mut self, (&'a K, &'a V))

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl Extend<OsString> for OsString

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = OsString>, 

impl Extend<()> for ()

pub fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = ()>, 

pub fn extend_one(&mut self, _item: ())

🔬 This is a nightly-only experimental API. (extend_one)

impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB) where
    ExtendA: Extend<A>,
    ExtendB: Extend<B>, 

pub fn extend<T>(&mut self, into_iter: T) where
    T: IntoIterator<Item = (A, B)>, 

Allows to extend a tuple of collections that also implement Extend.

See also: Iterator::unzip

Examples

let mut tuple = (vec![0], vec![1]);
tuple.extend([(2, 3), (4, 5), (6, 7)]);
assert_eq!(tuple.0, [0, 2, 4, 6]);
assert_eq!(tuple.1, [1, 3, 5, 7]);

// also allows for arbitrarily nested tuples as elements
let mut nested_tuple = (vec![1], (vec![2], vec![3]));
nested_tuple.extend([(4, (5, 6)), (7, (8, 9))]);

let (a, (b, c)) = nested_tuple;
assert_eq!(a, [1, 4, 7]);
assert_eq!(b, [2, 5, 8]);
assert_eq!(c, [3, 6, 9]);

pub fn extend_one(&mut self, item: (A, B))

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<T> Extend<T> for BinaryHeap<T> where
    T: Ord, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = T>, 

pub fn extend_one(&mut self, item: T)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a> Extend<&'a str> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a str>, 

pub fn extend_one(&mut self, s: &'a str)

🔬 This is a nightly-only experimental API. (extend_one)

impl Extend<char> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = char>, 

pub fn extend_one(&mut self, c: char)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a, T> Extend<&'a T> for LinkedList<T> where
    T: 'a + Copy, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a T>, 

pub fn extend_one(&mut self, &'a T)

🔬 This is a nightly-only experimental API. (extend_one)

impl Extend<Box<str, Global>> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = Box<str, Global>>, 

impl Extend<String> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = String>, 

pub fn extend_one(&mut self, s: String)

🔬 This is a nightly-only experimental API. (extend_one)

impl<T> Extend<T> for LinkedList<T>

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = T>, 

pub fn extend_one(&mut self, elem: T)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a> Extend<&'a char> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a char>, 

pub fn extend_one(&mut self, &'a char)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a, T> Extend<&'a T> for BinaryHeap<T> where
    T: 'a + Ord + Copy, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a T>, 

pub fn extend_one(&mut self, &'a T)

🔬 This is a nightly-only experimental API. (extend_one)

pub fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

impl<'a> Extend<Cow<'a, str>> for String

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = Cow<'a, str>>, 

pub fn extend_one(&mut self, s: Cow<'a, str>)

🔬 This is a nightly-only experimental API. (extend_one)

Implementors

impl<'a, K, V> Extend<(&'a K, &'a V)> for BTreeMap<K, V> where
    K: Ord + Copy,
    V: Copy, 

impl<'a, T> Extend<&'a T> for BTreeSet<T> where
    T: 'a + Ord + Copy, 

impl<'a, T, A> Extend<&'a T> for VecDeque<T, A> where
    T: 'a + Copy,
    A: Allocator, 

impl<'a, T, A> Extend<&'a T> for Vec<T, A> where
    T: 'a + Copy,
    A: 'a + Allocator, 

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.

impl<K, V> Extend<(K, V)> for BTreeMap<K, V> where
    K: Ord, 

impl<T> Extend<T> for BTreeSet<T> where
    T: Ord, 

impl<T, A> Extend<T> for VecDeque<T, A> where
    A: Allocator, 

impl<T, A> Extend<T> for Vec<T, A> where
    A: Allocator, 

impl<T, const CAP: usize> Extend<T> for ArrayVec<T, CAP>

impl<P: AsRef<Path>> Extend<P> for PathBuf

impl<O, T> Extend<bool> for BitVec<O, T> where
    O: BitOrder,
    T: BitStore, 

impl<'a, O, T> Extend<&'a bool> for BitVec<O, T> where
    O: BitOrder,
    T: BitStore, 

impl<'a, M, O1, O2, T1, T2> Extend<BitRef<'a, M, O2, T2>> for BitVec<O1, T1> where
    M: Mutability,
    O1: BitOrder,
    O2: BitOrder,
    T1: BitStore,
    T2: BitStore, 

impl<O, T> Extend<T> for BitVec<O, T> where
    O: BitOrder,
    T: BitStore, 

impl<'a, O, T> Extend<&'a T> for BitVec<O, T> where
    O: BitOrder,
    T: BitStore, 

impl Extend<u8> for BytesMut

impl<'a> Extend<&'a u8> for BytesMut

impl<L, R, A> Extend<A> for Either<L, R> where
    L: Extend<A>,
    R: Extend<A>, 

impl Extend<WithdrawReasons> for WithdrawReasons

impl<Fut: Future> Extend<Fut> for FuturesOrdered<Fut>

impl<Fut> Extend<Fut> for FuturesUnordered<Fut>

impl<St: Stream + Unpin> Extend<St> for SelectAll<St>

impl<K, V, S, A> Extend<(K, V)> for HashMap<K, V, S, A> where
    K: Eq + Hash,
    S: BuildHasher,
    A: Allocator + Clone, 

impl<'a, K, V, S, A> Extend<(&'a K, &'a V)> for HashMap<K, V, S, A> where
    K: Eq + Hash + Copy,
    V: Copy,
    S: BuildHasher,
    A: Allocator + Clone, 

impl<T, S, A> Extend<T> for HashSet<T, S, A> where
    T: Eq + Hash,
    S: BuildHasher,
    A: Allocator + Clone, 

impl<'a, T, S, A> Extend<&'a T> for HashSet<T, S, A> where
    T: 'a + Eq + Hash + Copy,
    S: BuildHasher,
    A: Allocator + Clone, 

impl<T> Extend<(Option<HeaderName>, T)> for HeaderMap<T>

impl<T> Extend<(HeaderName, T)> for HeaderMap<T>

impl<K, V, S> Extend<(K, V)> for IndexMap<K, V, S> where
    K: Hash + Eq,
    S: BuildHasher, 

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for IndexMap<K, V, S> where
    K: Hash + Eq + Copy,
    V: Copy,
    S: BuildHasher, 

impl<T, S> Extend<T> for IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher, 

impl<'a, T, S> Extend<&'a T> for IndexSet<T, S> where
    T: Hash + Eq + Copy + 'a,
    S: BuildHasher, 

impl<K: Hash + Eq, V, S: BuildHasher> Extend<(K, V)> for LinkedHashMap<K, V, S>

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for LinkedHashMap<K, V, S> where
    K: 'a + Hash + Eq + Copy,
    V: 'a + Copy,
    S: BuildHasher, 

impl<T, S> Extend<T> for LinkedHashSet<T, S> where
    T: Eq + Hash,
    S: BuildHasher, 

impl<'a, T, S> Extend<&'a T> for LinkedHashSet<T, S> where
    T: 'a + Eq + Hash + Copy,
    S: BuildHasher, 

impl<T, R, S> Extend<T> for Matrix<T, R, Dynamic, S> where
    T: Scalar,
    R: Dim,
    S: Extend<T>, 

impl<T, S> Extend<T> for Matrix<T, Dynamic, U1, S> where
    T: Scalar,
    S: Extend<T>, 

impl<T, R, S, RV, SV> Extend<Matrix<T, RV, Const<1_usize>, SV>> for Matrix<T, R, Dynamic, S> where
    T: Scalar,
    R: Dim,
    S: Extend<Vector<T, RV, SV>>,
    RV: Dim,
    SV: Storage<T, RV>,
    ShapeConstraint: SameNumberOfRows<R, RV>, 

impl<T, R: Dim> Extend<T> for VecStorage<T, R, Dynamic>

impl<'a, T: 'a + Copy, R: Dim> Extend<&'a T> for VecStorage<T, R, Dynamic>

impl<T, R, RV, SV> Extend<Matrix<T, RV, Const<1_usize>, SV>> for VecStorage<T, R, Dynamic> where
    T: Scalar,
    R: Dim,
    RV: Dim,
    SV: Storage<T, RV>,
    ShapeConstraint: SameNumberOfRows<R, RV>, 

impl<T> Extend<T> for VecStorage<T, Dynamic, U1>

impl Extend<TokenTree> for TokenStream

impl Extend<TokenStream> for TokenStream

impl Extend<Protection> for Protection

impl Extend<(String, Value)> for Map<String, Value>

impl<A: Array> Extend<<A as Array>::Item> for SmallVec<A>

impl<T, P> Extend<T> for Punctuated<T, P> where
    P: Default, 

impl<T, P> Extend<Pair<T, P>> for Punctuated<T, P>

impl Extend<Error> for Error

impl<A: Array> Extend<<A as Array>::Item> for ArrayVec<A>

impl<'s, T> Extend<T> for SliceVec<'s, T>

impl<A: Array> Extend<<A as Array>::Item> for TinyVec<A>

impl Extend<(String, Value)> for Map<String, Value>

impl<V> Extend<(usize, V)> for VecMap<V>

impl<'a, V: Copy> Extend<(usize, &'a V)> for VecMap<V>