Trait FromParallelIterator

pub trait FromParallelIterator<T>
where
    T: Send,
{
    // Required method
    fn from_par_iter<I>(par_iter: I) -> Self
       where I: IntoParallelIterator<Item = T>;
}

FromParallelIterator implements the creation of a collection from a ParallelIterator. By implementing FromParallelIterator for a given type, you define how it will be created from an iterator.

FromParallelIterator is used through ParallelIterator’s collect() method.

Examples

Implementing FromParallelIterator for your type:

use rayon::prelude::*;
use std::mem;

struct BlackHole {
    mass: usize,
}

impl<T: Send> FromParallelIterator<T> for BlackHole {
    fn from_par_iter<I>(par_iter: I) -> Self
        where I: IntoParallelIterator<Item = T>
    {
        let par_iter = par_iter.into_par_iter();
        BlackHole {
            mass: par_iter.count() * mem::size_of::<T>(),
        }
    }
}

let bh: BlackHole = (0i32..1000).into_par_iter().collect();
assert_eq!(bh.mass, 4000);

Required Methods

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

Creates an instance of the collection from the parallel iterator par_iter.

If your collection is not naturally parallel, the easiest (and fastest) way to do this is often to collect par_iter into a LinkedList (via collect_vec_list) or another intermediate data structure and then sequentially extend your collection. However, a more ‘native’ technique is to use the par_iter.fold or par_iter.fold_with methods to create the collection. Alternatively, if your collection is ‘natively’ parallel, you can use par_iter.for_each to process each element in turn.

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.

Implementations on Foreign Types

impl FromParallelIterator<char> for String

Collects characters from a parallel iterator into a string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = char>,

impl FromParallelIterator<()> for ()

Collapses all unit items from a parallel 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::*;
use rayon::prelude::*;

let data = vec![1, 2, 3, 4, 5];
let res: Result<()> = data.par_iter()
    .map(|x| writeln!(stdout(), "{}", x))
    .collect();
assert!(res.is_ok());

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = ()>,

impl FromParallelIterator<Box<str>> for String

Collects boxed strings from a parallel iterator into one large string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = Box<str>>,

impl FromParallelIterator<String> for String

Collects strings from a parallel iterator into one large string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = String>,

impl FromParallelIterator<OsString> for OsString

Collects OS-strings from a parallel iterator into one large OS-string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = OsString>,

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

Collects characters from a parallel iterator into a string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = &'a char>,

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

Collects string slices from a parallel iterator into a string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = &'a str>,

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

Collects OS-string slices from a parallel iterator into an OS-string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = &'a OsStr>,

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

Collects string slices from a parallel iterator into a string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = Cow<'a, str>>,

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

Collects OS-string slices from a parallel iterator into an OS-string.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = Cow<'a, OsStr>>,

impl<'a, C, T> FromParallelIterator<T> for Cow<'a, C>

where C: ToOwned + ?Sized, C::Owned: FromParallelIterator<T>, T: Send,

Collects an arbitrary Cow collection.

Note, the standard library only has FromIterator for Cow<'a, str> and Cow<'a, [T]>, because no one thought to add a blanket implementation before it was stabilized.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<A, B, FromA, FromB> FromParallelIterator<(A, B)> for (FromA, FromB)

where A: Send, B: Send, FromA: Send + FromParallelIterator<A>, FromB: Send + FromParallelIterator<B>,

fn from_par_iter<I>(pi: I) -> Self

where I: IntoParallelIterator<Item = (A, B)>,

impl<C, T> FromParallelIterator<Option<T>> for Option<C>

where C: FromParallelIterator<T>, T: Send,

Collect an arbitrary Option-wrapped collection.

If any item is None, then all previous items collected are discarded, and it returns only None.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = Option<T>>,

impl<C, T, E> FromParallelIterator<Result<T, E>> for Result<C, E>

where C: FromParallelIterator<T>, T: Send, E: Send,

Collect an arbitrary Result-wrapped collection.

If any item is Err, then all previous Ok items collected are discarded, and it returns that error. If there are multiple errors, the one returned is not deterministic.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = Result<T, E>>,

impl<K, V> FromParallelIterator<(K, V)> for BTreeMap<K, V>

where K: Ord + Send, V: Send,

Collects (key, value) pairs from a parallel iterator into a btreemap. If multiple pairs correspond to the same key, then the ones produced earlier in the parallel iterator will be overwritten, just as with a sequential iterator.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = (K, V)>,

impl<K, V, S> FromParallelIterator<(K, V)> for HashMap<K, V, S>

where K: Eq + Hash + Send, V: Send, S: BuildHasher + Default + Send,

Collects (key, value) pairs from a parallel iterator into a hashmap. If multiple pairs correspond to the same key, then the ones produced earlier in the parallel iterator will be overwritten, just as with a sequential iterator.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = (K, V)>,

impl<L, R, A, B> FromParallelIterator<Either<L, R>> for (A, B)

where L: Send, R: Send, A: Send + FromParallelIterator<L>, B: Send + FromParallelIterator<R>,

fn from_par_iter<I>(pi: I) -> Self

where I: IntoParallelIterator<Item = Either<L, R>>,

impl<T> FromParallelIterator<T> for Box<[T]>

where T: Send,

Collects items from a parallel iterator into a boxed slice.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for BinaryHeap<T>

where T: Ord + Send,

Collects items from a parallel iterator into a binaryheap. The heap-ordering is calculated serially after all items are collected.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for LinkedList<T>

where T: Send,

Collects items from a parallel iterator into a freshly allocated linked list.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for VecDeque<T>

where T: Send,

Collects items from a parallel iterator into a vecdeque.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for Rc<[T]>

where T: Send,

Collects items from a parallel iterator into a reference-counted slice.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for Arc<[T]>

where T: Send,

Collects items from a parallel iterator into an atomically-reference-counted slice.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<T> FromParallelIterator<T> for Vec<T>

where T: Send,

Collects items from a parallel iterator into a vector.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = T>,

impl<V> FromParallelIterator<V> for BTreeSet<V>

where V: Send + Ord,

Collects values from a parallel iterator into a btreeset.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = V>,

impl<V, S> FromParallelIterator<V> for HashSet<V, S>

where V: Eq + Hash + Send, S: BuildHasher + Default + Send,

Collects values from a parallel iterator into a hashset.

fn from_par_iter<I>(par_iter: I) -> Self

where I: IntoParallelIterator<Item = V>,

Implementors