Trait otter_nodejs_tests::inventory::core::prelude::rust_2024::FromIterator
1.0.0 · source · [−]pub trait FromIterator<A> {
fn from_iter<T>(iter: T) -> Self
where
T: IntoIterator<Item = A>;
}
Expand description
Conversion from an Iterator
.
By implementing FromIterator
for a type, you define how it will be
created from an iterator. This is common for types which describe a
collection of some kind.
If you want to create a collection from the contents of an iterator, the
Iterator::collect()
method is preferred. However, when you need to
specify the container type, FromIterator::from_iter()
can be more
readable than using a turbofish (e.g. ::<Vec<_>>()
). See the
Iterator::collect()
documentation for more examples of its use.
See also: IntoIterator
.
Examples
Basic usage:
let five_fives = std::iter::repeat(5).take(5);
let v = Vec::from_iter(five_fives);
assert_eq!(v, vec![5, 5, 5, 5, 5]);
Using Iterator::collect()
to implicitly use FromIterator
:
let five_fives = std::iter::repeat(5).take(5);
let v: Vec<i32> = five_fives.collect();
assert_eq!(v, vec![5, 5, 5, 5, 5]);
Using FromIterator::from_iter()
as a more readable alternative to
Iterator::collect()
:
use std::collections::VecDeque;
let first = (0..10).collect::<VecDeque<i32>>();
let second = VecDeque::from_iter(0..10);
assert_eq!(first, second);
Implementing FromIterator
for your type:
// 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);
}
}
// and we'll implement FromIterator
impl FromIterator<i32> for MyCollection {
fn from_iter<I: IntoIterator<Item=i32>>(iter: I) -> Self {
let mut c = MyCollection::new();
for i in iter {
c.add(i);
}
c
}
}
// Now we can make a new iterator...
let iter = (0..5).into_iter();
// ... and make a MyCollection out of it
let c = MyCollection::from_iter(iter);
assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
// collect works too!
let iter = (0..5).into_iter();
let c: MyCollection = iter.collect();
assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
Required Methods
fn from_iter<T>(iter: T) -> Self where
T: IntoIterator<Item = A>,
fn from_iter<T>(iter: T) -> Self where
T: IntoIterator<Item = A>,
Creates a value from an iterator.
See the module-level documentation for more.
Examples
Basic usage:
let five_fives = std::iter::repeat(5).take(5);
let v = Vec::from_iter(five_fives);
assert_eq!(v, vec![5, 5, 5, 5, 5]);
Implementors
impl FromIterator<(String, Value)> for otter_nodejs_tests::otter_support::crates::toml::value::Map<String, Value>
impl FromIterator<(String, Value)> for otter_nodejs_tests::tera::Map<String, Value>
impl FromIterator<Signal> for SigSet
impl FromIterator<char> for String
impl FromIterator<char> for BString
impl FromIterator<u8> for BString
impl FromIterator<u8> for Bytes
impl FromIterator<u8> for BytesMut
impl FromIterator<()> for ()
Collapses all unit items from an iterator into one.
This is more useful when combined with higher-level abstractions, like
collecting to a Result<(), E>
where you only care about errors:
use std::io::*;
let data = vec![1, 2, 3, 4, 5];
let res: Result<()> = data.iter()
.map(|x| writeln!(stdout(), "{x}"))
.collect();
assert!(res.is_ok());
impl FromIterator<AtFlags> for AtFlags
impl FromIterator<FallocateFlags> for FallocateFlags
impl FromIterator<FdFlag> for otter_nodejs_tests::otter_support::crates::nix::fcntl::FdFlag
impl FromIterator<OFlag> for OFlag
impl FromIterator<RenameFlags> for RenameFlags
impl FromIterator<SealFlag> for SealFlag
impl FromIterator<SpliceFFlags> for SpliceFFlags
impl FromIterator<DeleteModuleFlags> for DeleteModuleFlags
impl FromIterator<ModuleInitFlags> for ModuleInitFlags
impl FromIterator<MntFlags> for MntFlags
impl FromIterator<MsFlags> for otter_nodejs_tests::otter_support::crates::nix::mount::MsFlags
impl FromIterator<FdFlag> for otter_nodejs_tests::otter_support::crates::nix::mqueue::FdFlag
impl FromIterator<MQ_OFlag> for MQ_OFlag
impl FromIterator<InterfaceFlags> for InterfaceFlags
impl FromIterator<PollFlags> for PollFlags
impl FromIterator<CloneFlags> for CloneFlags
impl FromIterator<EpollCreateFlags> for EpollCreateFlags
impl FromIterator<EpollFlags> for EpollFlags
impl FromIterator<EfdFlags> for EfdFlags
impl FromIterator<AddWatchFlags> for AddWatchFlags
impl FromIterator<InitFlags> for InitFlags
impl FromIterator<MemFdCreateFlag> for MemFdCreateFlag
impl FromIterator<MRemapFlags> for MRemapFlags
impl FromIterator<MapFlags> for MapFlags
impl FromIterator<MlockAllFlags> for MlockAllFlags
impl FromIterator<MsFlags> for otter_nodejs_tests::otter_support::crates::nix::sys::mman::MsFlags
impl FromIterator<ProtFlags> for ProtFlags
impl FromIterator<Persona> for Persona
impl FromIterator<Options> for Options
impl FromIterator<QuotaValidFlags> for QuotaValidFlags
impl FromIterator<SaFlags> for SaFlags
impl FromIterator<SfdFlags> for SfdFlags
impl FromIterator<MsgFlags> for MsgFlags
impl FromIterator<SockFlag> for SockFlag
impl FromIterator<TimestampingFlag> for TimestampingFlag
impl FromIterator<Mode> for Mode
impl FromIterator<SFlag> for SFlag
impl FromIterator<FsFlags> for FsFlags
impl FromIterator<ControlFlags> for ControlFlags
impl FromIterator<InputFlags> for InputFlags
impl FromIterator<LocalFlags> for LocalFlags
impl FromIterator<OutputFlags> for OutputFlags
impl FromIterator<TimerSetTimeFlags> for TimerSetTimeFlags
impl FromIterator<TimerFlags> for TimerFlags
impl FromIterator<WaitPidFlag> for WaitPidFlag
impl FromIterator<AccessFlags> for AccessFlags
impl FromIterator<Box<str, Global>> for String
impl FromIterator<String> for String
impl FromIterator<OsString> for OsString
impl FromIterator<CMSOptions> for CMSOptions
impl FromIterator<OcspFlag> for OcspFlag
impl FromIterator<Pkcs7Flags> for Pkcs7Flags
impl FromIterator<ExtensionContext> for ExtensionContext
impl FromIterator<ShutdownState> for ShutdownState
impl FromIterator<SslMode> for SslMode
impl FromIterator<SslOptions> for SslOptions
impl FromIterator<SslSessionCacheMode> for SslSessionCacheMode
impl FromIterator<SslVerifyMode> for SslVerifyMode
impl FromIterator<X509CheckFlags> for X509CheckFlags
impl FromIterator<X509VerifyFlags> for X509VerifyFlags
impl FromIterator<BString> for BString
impl FromIterator<EventMask> for EventMask
impl FromIterator<FileType> for FileType
impl FromIterator<Op> for Op
impl FromIterator<Transformations> for Transformations
impl FromIterator<WatchMask> for WatchMask
impl<'a> FromIterator<&'a char> for String
impl<'a> FromIterator<&'a str> for String
impl<'a> FromIterator<&'a str> for BString
impl<'a> FromIterator<&'a u8> for BytesMut
impl<'a> FromIterator<&'a OsStr> for OsString
impl<'a> FromIterator<&'a BStr> for BString
impl<'a> FromIterator<&'a [u8]> for BString
impl<'a> FromIterator<(Ident<'a>, Value<'a>)> for ParamsString
impl<'a> FromIterator<Cow<'a, str>> for String
impl<'a> FromIterator<Cow<'a, OsStr>> for OsString
impl<'a> FromIterator<char> for Cow<'a, str>
impl<'a> FromIterator<String> for Cow<'a, str>
impl<'a, 'b> FromIterator<&'b str> for Cow<'a, str>
impl<'a, T> FromIterator<T> for Cow<'a, [T]> where
T: Clone,
impl<A> FromIterator<<A as Array>::Item> for ArrayVec<A> where
A: Array,
impl<A> FromIterator<<A as Array>::Item> for SmallVec<A> where
A: Array,
impl<A> FromIterator<<A as Array>::Item> for TinyVec<A> where
A: Array,
impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E> where
V: FromIterator<A>,
impl<A, V> FromIterator<Option<A>> for Option<V> where
V: FromIterator<A>,
impl<EntryData> FromIterator<EntryData> for VecList<EntryData>
impl<F> FromIterator<F> for JoinAll<F> where
F: Future,
impl<F> FromIterator<F> for TryJoinAll<F> where
F: TryFuture,
impl<Fut> FromIterator<Fut> for FuturesOrdered<Fut> where
Fut: Future,
impl<Fut> FromIterator<Fut> for FuturesUnordered<Fut>
impl<Fut> FromIterator<Fut> for SelectAll<Fut> where
Fut: Future + Unpin,
impl<Fut> FromIterator<Fut> for SelectOk<Fut> where
Fut: TryFuture + Unpin,
impl<I> FromIterator<I> for Box<[I], Global>
impl<I, A> FromIterator<A> for Box<IndexSlice<I, [A]>, Global> where
I: Idx,
impl<I, T> FromIterator<T> for IndexVec<I, T> where
I: Idx,
impl<K, V> FromIterator<(K, V)> for Value where
K: Into<String>,
V: Into<Value>,
impl<K, V> FromIterator<(K, V)> for SecondaryMap<K, V> where
K: Key,
impl<K, V> FromIterator<(K, V)> for BTreeMap<K, V, Global> where
K: Ord,
impl<K, V> FromIterator<(K, V)> for EnumMap<K, V> where
K: EnumArray<V>,
EnumMap<K, V>: Default,
impl<K, V, S> FromIterator<(K, V)> for otter_nodejs_tests::HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher + Default,
impl<K, V, S> FromIterator<(K, V)> for IndexMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher + Default,
impl<K, V, S> FromIterator<(K, V)> for SparseSecondaryMap<K, V, S> where
K: Key,
S: BuildHasher + Default,
impl<K, V, S, A> FromIterator<(K, V)> for HashMap<K, V, S, A> where
K: Eq + Hash,
S: BuildHasher + Default,
A: Default + Allocator + Clone,
impl<P> FromIterator<P> for PathBuf where
P: AsRef<Path>,
impl<St> FromIterator<St> for SelectAll<St> where
St: Stream + Unpin,
impl<T> FromIterator<(usize, T)> for Slab<T>
Create a slab from an iterator of key-value pairs.
If the iterator produces duplicate keys, the previous value is replaced with the later one.
The keys does not need to be sorted beforehand, and this function always
takes O(n) time.
Note that the returned slab will use space proportional to the largest key,
so don’t use Slab
with untrusted keys.
Examples
let vec = vec![(2,'a'), (6,'b'), (7,'c')];
let slab = vec.into_iter().collect::<Slab<char>>();
assert_eq!(slab.len(), 3);
assert!(slab.capacity() >= 8);
assert_eq!(slab[2], 'a');
With duplicate and unsorted keys:
let vec = vec![(20,'a'), (10,'b'), (11,'c'), (10,'d')];
let slab = vec.into_iter().collect::<Slab<char>>();
assert_eq!(slab.len(), 3);
assert_eq!(slab[10], 'd');
impl<T> FromIterator<(HeaderName, T)> for HeaderMap<T>
impl<T> FromIterator<T> for Value where
T: Into<Value>,
impl<T> FromIterator<T> for Arc<[T]>
impl<T> FromIterator<T> for BTreeSet<T, Global> where
T: Ord,
impl<T> FromIterator<T> for VecDeque<T, Global>
impl<T> FromIterator<T> for BinaryHeap<T> where
T: Ord,
impl<T> FromIterator<T> for LinkedList<T>
impl<T> FromIterator<T> for Rc<[T]>
impl<T> FromIterator<T> for Vec<T, Global>
impl<T, N> FromIterator<T> for GenericArray<T, N> where
N: ArrayLength<T>,
impl<T, S> FromIterator<T> for otter_nodejs_tests::HashSet<T, S> where
T: Eq + Hash,
S: BuildHasher + Default,
impl<T, S> FromIterator<T> for IndexSet<T, S> where
T: Hash + Eq,
S: BuildHasher + Default,
impl<T, S, A> FromIterator<T> for HashSet<T, S, A> where
T: Eq + Hash,
S: BuildHasher + Default,
A: Default + Allocator + Clone,
impl<T, const CAP: usize> FromIterator<T> for otter_nodejs_tests::ArrayVec<T, CAP>
Create an ArrayVec
from an iterator.
Panics if the number of elements in the iterator exceeds the arrayvec’s capacity.