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 · Sourcefn extend<T>(&mut self, iter: T)where
T: IntoIterator<Item = A>,
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§
Sourcefn extend_one(&mut self, item: A)
🔬This is a nightly-only experimental API. (extend_one)
fn extend_one(&mut self, item: A)
extend_one)Extends a collection with exactly one element.
Sourcefn extend_reserve(&mut self, additional: usize)
🔬This is a nightly-only experimental API. (extend_one)
fn extend_reserve(&mut self, additional: usize)
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", so this trait is not object safe.
Implementors§
impl Extend<(String, Value)> for Map<String, Value>
impl Extend<AsciiChar> for String
no_global_oom_handling only.impl Extend<TokenTree> for proc_macro::TokenStream
impl Extend<TokenTree> for proc_macro2::TokenStream
impl Extend<char> for String
no_global_oom_handling only.impl Extend<u8> for BytesMut
impl Extend<()> for ()
impl Extend<usize> for FixedBitSet
Sets the bit at index i to true for each item i in the input src.
impl Extend<Bytes> for BytesMut
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
impl Extend<X509CheckFlags> for X509CheckFlags
impl Extend<X509VerifyFlags> for X509VerifyFlags
impl Extend<String> for String
no_global_oom_handling only.impl Extend<TrustAnchor<'static>> for RootCertStore
impl Extend<Group> for proc_macro::TokenStream
impl Extend<Ident> for proc_macro::TokenStream
impl Extend<Literal> for proc_macro::TokenStream
impl Extend<Punct> for proc_macro::TokenStream
impl Extend<TokenStream> for proc_macro::TokenStream
impl Extend<OsString> for OsString
impl Extend<Group> for proc_macro2::TokenStream
impl Extend<Ident> for proc_macro2::TokenStream
impl Extend<Literal> for proc_macro2::TokenStream
impl Extend<Punct> for proc_macro2::TokenStream
impl Extend<TokenStream> for proc_macro2::TokenStream
impl Extend<Error> for Error
impl Extend<Access> for Access
impl Extend<AtFlags> for AtFlags
impl Extend<CreateFlags> for CreateFlags
impl Extend<DupFlags> for DupFlags
impl Extend<FallocateFlags> for FallocateFlags
impl Extend<FdFlags> for FdFlags
impl Extend<IFlags> for IFlags
impl Extend<MemfdFlags> for MemfdFlags
impl Extend<Mode> for Mode
impl Extend<OFlags> for OFlags
impl Extend<ReadFlags> for ReadFlags
impl Extend<ReadWriteFlags> for ReadWriteFlags
impl Extend<RenameFlags> for RenameFlags
impl Extend<ResolveFlags> for ResolveFlags
impl Extend<SealFlags> for SealFlags
impl Extend<StatVfsMountFlags> for StatVfsMountFlags
impl Extend<StatxAttributes> for StatxAttributes
impl Extend<StatxFlags> for StatxFlags
impl Extend<Table> for ArrayOfTables
impl Extend<WatchFlags> for WatchFlags
impl Extend<XattrFlags> for XattrFlags
impl<'a> Extend<&'a AsciiChar> for String
no_global_oom_handling only.impl<'a> Extend<&'a char> for String
no_global_oom_handling only.impl<'a> Extend<&'a str> for String
no_global_oom_handling only.impl<'a> Extend<&'a u8> for BytesMut
impl<'a> Extend<&'a u8> for PrefixedPayload
impl<'a> Extend<&'a OsStr> for OsString
impl<'a> Extend<Cow<'a, str>> for String
no_global_oom_handling only.impl<'a> Extend<Cow<'a, OsStr>> for OsString
impl<'a, K, V, A> Extend<(&'a K, &'a V)> for BTreeMap<K, V, A>
impl<'a, K, V, S> Extend<(&'a K, &'a Vec<V>)> for MultiMap<K, V, S>
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for AHashMap<K, V, S>
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for IndexMap<K, V, S>
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for MultiMap<K, V, S>
impl<'a, K, V, S, A> Extend<&'a (K, V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<'a, K, V, S, A> Extend<&'a (K, V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<'a, K, V, S, A> Extend<(&'a K, &'a V)> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::collections::HashMap<K, V, S, A>
impl<'a, K, V, S, A> Extend<(&'a K, &'a V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<'a, K, V, S, A> Extend<(&'a K, &'a V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<'a, T, A> Extend<&'a T> for rama::http::grpc::protobuf::prost::alloc::vec::Vec<T, A>
no_global_oom_handling only.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<'a, T, A> Extend<&'a T> for BTreeSet<T, A>
impl<'a, T, A> Extend<&'a T> for BinaryHeap<T, A>
impl<'a, T, A> Extend<&'a T> for LinkedList<T, A>
impl<'a, T, A> Extend<&'a T> for VecDeque<T, A>
impl<'a, T, A> Extend<&'a T> for Vec<T, A>where
T: Copy + 'a,
A: Allocator + 'a,
no_global_oom_handling only.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<'a, T, S> Extend<&'a T> for AHashSet<T, S>
impl<'a, T, S> Extend<&'a T> for IndexSet<T, S>
impl<'a, T, S, A> Extend<&'a T> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::collections::HashSet<T, S, A>
impl<'a, T, S, A> Extend<&'a T> for HashSet<T, S, A>
impl<'a, T, S, A> Extend<&'a T> for HashSet<T, S, A>
impl<'s, T> Extend<T> for SliceVec<'s, T>
impl<A> Extend<<A as Array>::Item> for SmallVec<A>where
A: Array,
impl<A> Extend<<A as Array>::Item> for ArrayVec<A>where
A: Array,
impl<A> Extend<<A as Array>::Item> for TinyVec<A>where
A: Array,
impl<A> Extend<Box<str, A>> for Stringwhere
A: Allocator,
no_global_oom_handling only.impl<A> Extend<A> for NonEmptyVec<A>
impl<A> Extend<Box<str, A>> for Stringwhere
A: Allocator,
alloc only.impl<Fut> Extend<Fut> for FuturesOrdered<Fut>where
Fut: Future,
impl<Fut> Extend<Fut> for FuturesUnordered<Fut>
impl<K, V> Extend<(K, V)> for StreamMap<K, V>
impl<K, V> Extend<(K, V)> for InlineTable
impl<K, V> Extend<(K, V)> for Table
impl<K, V, A> Extend<(K, V)> for BTreeMap<K, V, A>
impl<K, V, S> Extend<(K, Vec<V>)> for MultiMap<K, V, S>
impl<K, V, S> Extend<(K, V)> for AHashMap<K, V, S>
impl<K, V, S> Extend<(K, V)> for IndexMap<K, V, S>
impl<K, V, S> Extend<(K, V)> for LiteMap<K, V, S>where
K: Ord,
S: StoreBulkMut<K, V>,
impl<K, V, S> Extend<(K, V)> for MultiMap<K, V, S>
impl<K, V, S, A> Extend<(K, V)> for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::lib::std::collections::HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<K, V, S, A> Extend<(K, V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<K, V, S, A> Extend<(K, V)> for HashMap<K, V, S, A>
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
impl<L, R, A> Extend<A> for Either<L, R>
impl<P> Extend<P> for PathBuf
impl<St> Extend<St> for SelectAll<St>
impl<T> Extend<(Option<HeaderName>, T)> for HeaderMap<T>
impl<T> Extend<(HeaderName, T)> for HeaderMap<T>
impl<T> Extend<T> for ByteRecord
impl<T> Extend<T> for StringRecord
impl<T, A> Extend<T> for rama::http::grpc::protobuf::prost::alloc::vec::Vec<T, A>where
A: Allocator,
no_global_oom_handling only.impl<T, A> Extend<T> for BTreeSet<T, A>
impl<T, A> Extend<T> for BinaryHeap<T, A>
impl<T, A> Extend<T> for LinkedList<T, A>where
A: Allocator,
impl<T, A> Extend<T> for VecDeque<T, A>where
A: Allocator,
impl<T, A> Extend<T> for Vec<T, A>where
A: Allocator,
no_global_oom_handling only.impl<T, ExtendT> Extend<(T₁, T₂, …, Tₙ)> for (ExtendT₁, ExtendT₂, …, ExtendTₙ)where
ExtendT: Extend<T>,
This trait is implemented for tuples up to twelve items long. The impls for
1- and 3- through 12-ary tuples were stabilized after 2-tuples, in 1.85.0.
impl<T, F> Extend<F> for JoinSet<T>
Extend a [JoinSet] with futures from an iterator.
This is equivalent to calling [JoinSet::spawn] on each element of the iterator.
§Examples
use tokio::task::JoinSet;
#[tokio::main]
async fn main() {
let mut set: JoinSet<_> = (0..5).map(|i| async move { i }).collect();
set.extend((5..10).map(|i| async move { i }));
let mut seen = [false; 10];
while let Some(res) = set.join_next().await {
let idx = res.unwrap();
seen[idx] = true;
}
for i in 0..10 {
assert!(seen[i]);
}
}