Trait sp_std::iter::Extend

[+] Show declaration

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) { ... }
}

[−] Expand description

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<T, S> Extend<T> for HashSet<T, S> where
    S: BuildHasher,
    T: Eq + Hash, [−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, item: T)

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

fn extend_reserve(&mut self, additional: usize)

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

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

[+] Show hidden undocumented items

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

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

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

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>, [−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, p: P)

🔬 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, [−]

[−] Expand description

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

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

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

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

impl Extend<()> for ()[−]

[+] Show hidden undocumented items

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

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

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

impl<'a> Extend<&'a str> for String[−]

[+] Show hidden undocumented items

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

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

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

impl<T> Extend<T> for LinkedList<T>[−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, elem: T)

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

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

[+] Show hidden undocumented items

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

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

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

impl<T> Extend<T> for BinaryHeap<T> where
    T: Ord, [−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, item: T)

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

fn extend_reserve(&mut self, additional: usize)

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

impl<'a> Extend<Cow<'a, str>> for String[−]

[+] Show hidden undocumented items

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

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

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

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

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

impl Extend<char> for String[−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, c: char)

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

fn extend_reserve(&mut self, additional: usize)

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

impl Extend<Box<str>> for String[−]

[+] Show hidden undocumented items

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

impl<'a> Extend<&'a char> for String[−]

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

impl Extend<String> for String[−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, s: String)

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

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

[+] Show hidden undocumented items

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

fn extend_one(&mut self, k: &'a T)

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

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
    S: BuildHasher,
    T: Eq + Hash, [−]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, k: T)

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

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, [−]

[−] Expand description

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

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

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

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

🔬 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, [+]

[+] Show hidden undocumented items

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

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

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

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

[+] Show hidden undocumented items

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

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

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

impl<'a, T> Extend<&'a T> for VecDeque<T> where
    T: 'a + Copy, [+]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, &T)

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

fn extend_reserve(&mut self, additional: usize)

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

impl<'a, T> Extend<&'a T> for Vec<T> where
    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.

[+] Show hidden undocumented items

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

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

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

fn extend_reserve(&mut self, additional: usize)

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

impl<A> Extend<A> for VecDeque<A>[+]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, elem: A)

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

fn extend_reserve(&mut self, additional: usize)

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

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

[+] Show hidden undocumented items

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

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

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

impl<T> Extend<T> for BTreeSet<T> where
    T: Ord, [+]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, elem: T)

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

impl<T> Extend<T> for Vec<T>[+]

[+] Show hidden undocumented items

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

fn extend_one(&mut self, item: T)

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

fn extend_reserve(&mut self, additional: usize)

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

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

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

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

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

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

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

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

impl Extend<TokenTree> for TokenStream

impl Extend<TokenStream> for TokenStream

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