Trait Extend

1.0.0 · Source

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

    // Provided methods
    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§

1.0.0 · Source

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

// 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§

Source

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

Source

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.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Trait Extend Copy item path

§Examples

Required Methods§

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

§Examples

Provided Methods§

fn extend_one(&mut self, item: A)

fn extend_reserve(&mut self, additional: usize)

Dyn Compatibility§

Implementors§

impl Extend<(String, Value)> for otter_nodejs_tests::tera::Map<String, Value>

impl Extend<(String, Value)> for otter_nodejs_tests::toml::map::Map<String, Value>

impl Extend<AsciiChar> for String

impl Extend<Signal> for SigSet

impl Extend<char> for String

impl Extend<u8> for BytesMut

impl Extend<()> for ()

impl Extend<AtFlags> for otter_nodejs_tests::nix::fcntl::AtFlags

impl Extend<FallocateFlags> for otter_nodejs_tests::nix::fcntl::FallocateFlags

impl Extend<FdFlag> for otter_nodejs_tests::nix::fcntl::FdFlag

impl Extend<OFlag> for OFlag

impl Extend<RenameFlags> for otter_nodejs_tests::nix::fcntl::RenameFlags

impl Extend<SealFlag> for SealFlag

impl Extend<SpliceFFlags> for SpliceFFlags

impl Extend<DeleteModuleFlags> for DeleteModuleFlags

impl Extend<ModuleInitFlags> for ModuleInitFlags

impl Extend<MntFlags> for MntFlags

impl Extend<MsFlags> for otter_nodejs_tests::nix::mount::MsFlags

impl Extend<FdFlag> for otter_nodejs_tests::nix::mqueue::FdFlag

impl Extend<MQ_OFlag> for MQ_OFlag

impl Extend<InterfaceFlags> for InterfaceFlags

impl Extend<PollFlags> for PollFlags

impl Extend<CloneFlags> for CloneFlags

impl Extend<EpollCreateFlags> for EpollCreateFlags

impl Extend<EpollFlags> for EpollFlags

impl Extend<EfdFlags> for EfdFlags

impl Extend<AddWatchFlags> for AddWatchFlags

impl Extend<InitFlags> for InitFlags

impl Extend<MemFdCreateFlag> for MemFdCreateFlag

impl Extend<MRemapFlags> for MRemapFlags

impl Extend<MapFlags> for MapFlags

impl Extend<MlockAllFlags> for MlockAllFlags

impl Extend<MsFlags> for otter_nodejs_tests::nix::sys::mman::MsFlags

impl Extend<ProtFlags> for ProtFlags

impl Extend<Persona> for Persona

impl Extend<Options> for Options

impl Extend<QuotaValidFlags> for QuotaValidFlags

impl Extend<SaFlags> for SaFlags

impl Extend<SfdFlags> for SfdFlags

impl Extend<MsgFlags> for MsgFlags

impl Extend<SockFlag> for SockFlag

impl Extend<TimestampingFlag> for TimestampingFlag

impl Extend<Mode> for otter_nodejs_tests::nix::sys::stat::Mode

impl Extend<SFlag> for SFlag

impl Extend<FsFlags> for FsFlags

impl Extend<ControlFlags> for ControlFlags

impl Extend<InputFlags> for InputFlags

impl Extend<LocalFlags> for LocalFlags

impl Extend<OutputFlags> for OutputFlags

impl Extend<TimerFlags> for TimerFlags

impl Extend<TimerSetTimeFlags> for TimerSetTimeFlags

impl Extend<WaitPidFlag> for WaitPidFlag

impl Extend<AccessFlags> for AccessFlags

impl Extend<String> for String

impl Extend<OsString> for OsString

impl Extend<Bytes> for BytesMut

impl Extend<FileType> for FileType

impl Extend<EventMask> for EventMask

impl Extend<WatchMask> for WatchMask

impl Extend<Op> for Op

impl Extend<CipherCtxFlags> for CipherCtxFlags

impl Extend<CMSOptions> for CMSOptions

impl Extend<OcspFlag> for OcspFlag

impl Extend<Pkcs7Flags> for Pkcs7Flags

impl Extend<ExtensionContext> for ExtensionContext

impl Extend<ShutdownState> for ShutdownState

impl Extend<SslMode> for SslMode

impl Extend<SslOptions> for SslOptions

impl Extend<SslSessionCacheMode> for SslSessionCacheMode

impl Extend<SslVerifyMode> for SslVerifyMode

Trait Extend

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

impl<'a, I, T> Extend<&'a T> for IndexVec<I, T>
where I: Idx, T: 'a + Copy,

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

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

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

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

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

impl<'a, K, V, S> Extend<(K, &'a V)> for SparseSecondaryMap<K, V, S>
where K: Key, V: 'a + Copy, S: BuildHasher,

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

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

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

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

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

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

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 BinaryHeap<T, A>
where T: 'a + Ord + Copy, A: Allocator,

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

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

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

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

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

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

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

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

impl<'entries, EntryData> Extend<&'entries EntryData> for VecList<EntryData>
where EntryData: 'entries + Copy,

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

impl<A> Extend<Box<str, A>> for String
where A: Allocator,

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

impl<I, T> Extend<T> for IndexVec<I, T>
where I: Idx,

impl<K, V> Extend<(K, V)> for SecondaryMap<K, V>
where K: Key,