Struct rayon::iter::Once

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pub struct Once<T: Send> { /* private fields */ }
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Iterator adaptor for the once() function.

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impl<T: Clone + Send> Clone for Once<T>

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fn clone(&self) -> Once<T>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T: Debug + Send> Debug for Once<T>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<T: Send> IndexedParallelIterator for Once<T>

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fn drive<C>(self, consumer: C) -> C::Resultwhere C: Consumer<Self::Item>,

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly. Read more
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fn len(&self) -> usize

Produces an exact count of how many items this iterator will produce, presuming no panic occurs. Read more
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fn with_producer<CB>(self, callback: CB) -> CB::Outputwhere CB: ProducerCallback<Self::Item>,

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly. Read more
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fn collect_into_vec(self, target: &mut Vec<Self::Item>)

Collects the results of the iterator into the specified vector. The vector is always truncated before execution begins. If possible, reusing the vector across calls can lead to better performance since it reuses the same backing buffer. Read more
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fn unzip_into_vecs<A, B>(self, left: &mut Vec<A>, right: &mut Vec<B>)where Self: IndexedParallelIterator<Item = (A, B)>, A: Send, B: Send,

Unzips the results of the iterator into the specified vectors. The vectors are always truncated before execution begins. If possible, reusing the vectors across calls can lead to better performance since they reuse the same backing buffer. Read more
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fn zip<Z>(self, zip_op: Z) -> Zip<Self, Z::Iter>where Z: IntoParallelIterator, Z::Iter: IndexedParallelIterator,

Iterate over tuples (A, B), where the items A are from this iterator and B are from the iterator given as argument. Like the zip method on ordinary iterators, if the two iterators are of unequal length, you only get the items they have in common. Read more
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fn zip_eq<Z>(self, zip_op: Z) -> ZipEq<Self, Z::Iter>where Z: IntoParallelIterator, Z::Iter: IndexedParallelIterator,

The same as Zip, but requires that both iterators have the same length. Read more
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fn interleave<I>(self, other: I) -> Interleave<Self, I::Iter>where I: IntoParallelIterator<Item = Self::Item>, I::Iter: IndexedParallelIterator<Item = Self::Item>,

Interleave elements of this iterator and the other given iterator. Alternately yields elements from this iterator and the given iterator, until both are exhausted. If one iterator is exhausted before the other, the last elements are provided from the other. Read more
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fn interleave_shortest<I>(self, other: I) -> InterleaveShortest<Self, I::Iter>where I: IntoParallelIterator<Item = Self::Item>, I::Iter: IndexedParallelIterator<Item = Self::Item>,

Interleave elements of this iterator and the other given iterator, until one is exhausted. Read more
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fn chunks(self, chunk_size: usize) -> Chunks<Self>

Split an iterator up into fixed-size chunks. Read more
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fn partial_cmp<I>(self, other: I) -> Option<Ordering>where I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialOrd<I::Item>,

Lexicographically compares the elements of this ParallelIterator with those of another. Read more
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fn eq<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialEq<I::Item>,

Determines if the elements of this ParallelIterator are equal to those of another
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fn ne<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialEq<I::Item>,

Determines if the elements of this ParallelIterator are unequal to those of another
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fn lt<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialOrd<I::Item>,

Determines if the elements of this ParallelIterator are lexicographically less than those of another.
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fn le<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialOrd<I::Item>,

Determines if the elements of this ParallelIterator are less or equal to those of another.
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fn gt<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialOrd<I::Item>,

Determines if the elements of this ParallelIterator are lexicographically greater than those of another.
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fn ge<I>(self, other: I) -> boolwhere I: IntoParallelIterator, I::Iter: IndexedParallelIterator, Self::Item: PartialOrd<I::Item>,

Determines if the elements of this ParallelIterator are less or equal to those of another.
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fn enumerate(self) -> Enumerate<Self>

Yields an index along with each item. Read more
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fn skip(self, n: usize) -> Skip<Self>

Creates an iterator that skips the first n elements. Read more
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fn take(self, n: usize) -> Take<Self>

Creates an iterator that yields the first n elements. Read more
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fn position_any<P>(self, predicate: P) -> Option<usize>where P: Fn(Self::Item) -> bool + Sync + Send,

Searches for some item in the parallel iterator that matches the given predicate, and returns its index. Like ParallelIterator::find_any, the parallel search will not necessarily find the first match, and once a match is found we’ll attempt to stop processing any more. Read more
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fn position_first<P>(self, predicate: P) -> Option<usize>where P: Fn(Self::Item) -> bool + Sync + Send,

Searches for the sequentially first item in the parallel iterator that matches the given predicate, and returns its index. Read more
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fn position_last<P>(self, predicate: P) -> Option<usize>where P: Fn(Self::Item) -> bool + Sync + Send,

Searches for the sequentially last item in the parallel iterator that matches the given predicate, and returns its index. Read more
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fn rev(self) -> Rev<Self>

Produces a new iterator with the elements of this iterator in reverse order. Read more
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fn with_min_len(self, min: usize) -> MinLen<Self>

Sets the minimum length of iterators desired to process in each thread. Rayon will not split any smaller than this length, but of course an iterator could already be smaller to begin with. Read more
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fn with_max_len(self, max: usize) -> MaxLen<Self>

Sets the maximum length of iterators desired to process in each thread. Rayon will try to split at least below this length, unless that would put it below the length from with_min_len(). For example, given min=10 and max=15, a length of 16 will not be split any further. Read more
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impl<T: Send> ParallelIterator for Once<T>

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type Item = T

The type of item that this parallel iterator produces. For example, if you use the for_each method, this is the type of item that your closure will be invoked with.
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fn drive_unindexed<C>(self, consumer: C) -> C::Resultwhere C: UnindexedConsumer<Self::Item>,

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly. Read more
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fn opt_len(&self) -> Option<usize>

Internal method used to define the behavior of this parallel iterator. You should not need to call this directly. Read more
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fn for_each<OP>(self, op: OP)where OP: Fn(Self::Item) + Sync + Send,

Executes OP on each item produced by the iterator, in parallel. Read more
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fn for_each_with<OP, T>(self, init: T, op: OP)where OP: Fn(&mut T, Self::Item) + Sync + Send, T: Send + Clone,

Executes OP on the given init value with each item produced by the iterator, in parallel. Read more
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fn for_each_init<OP, INIT, T>(self, init: INIT, op: OP)where OP: Fn(&mut T, Self::Item) + Sync + Send, INIT: Fn() -> T + Sync + Send,

Executes OP on a value returned by init with each item produced by the iterator, in parallel. Read more
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fn try_for_each<OP, R>(self, op: OP) -> Rwhere OP: Fn(Self::Item) -> R + Sync + Send, R: Try<Ok = ()> + Send,

Executes a fallible OP on each item produced by the iterator, in parallel. Read more
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fn try_for_each_with<OP, T, R>(self, init: T, op: OP) -> Rwhere OP: Fn(&mut T, Self::Item) -> R + Sync + Send, T: Send + Clone, R: Try<Ok = ()> + Send,

Executes a fallible OP on the given init value with each item produced by the iterator, in parallel. Read more
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fn try_for_each_init<OP, INIT, T, R>(self, init: INIT, op: OP) -> Rwhere OP: Fn(&mut T, Self::Item) -> R + Sync + Send, INIT: Fn() -> T + Sync + Send, R: Try<Ok = ()> + Send,

Executes a fallible OP on a value returned by init with each item produced by the iterator, in parallel. Read more
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fn count(self) -> usize

Counts the number of items in this parallel iterator. Read more
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fn map<F, R>(self, map_op: F) -> Map<Self, F>where F: Fn(Self::Item) -> R + Sync + Send, R: Send,

Applies map_op to each item of this iterator, producing a new iterator with the results. Read more
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fn map_with<F, T, R>(self, init: T, map_op: F) -> MapWith<Self, T, F>where F: Fn(&mut T, Self::Item) -> R + Sync + Send, T: Send + Clone, R: Send,

Applies map_op to the given init value with each item of this iterator, producing a new iterator with the results. Read more
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fn map_init<F, INIT, T, R>( self, init: INIT, map_op: F ) -> MapInit<Self, INIT, F>where F: Fn(&mut T, Self::Item) -> R + Sync + Send, INIT: Fn() -> T + Sync + Send, R: Send,

Applies map_op to a value returned by init with each item of this iterator, producing a new iterator with the results. Read more
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fn cloned<'a, T>(self) -> Cloned<Self>where T: 'a + Clone + Send, Self: ParallelIterator<Item = &'a T>,

Creates an iterator which clones all of its elements. This may be useful when you have an iterator over &T, but you need T, and that type implements Clone. See also copied(). Read more
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fn copied<'a, T>(self) -> Copied<Self>where T: 'a + Copy + Send, Self: ParallelIterator<Item = &'a T>,

Creates an iterator which copies all of its elements. This may be useful when you have an iterator over &T, but you need T, and that type implements Copy. See also cloned(). Read more
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fn inspect<OP>(self, inspect_op: OP) -> Inspect<Self, OP>where OP: Fn(&Self::Item) + Sync + Send,

Applies inspect_op to a reference to each item of this iterator, producing a new iterator passing through the original items. This is often useful for debugging to see what’s happening in iterator stages. Read more
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fn update<F>(self, update_op: F) -> Update<Self, F>where F: Fn(&mut Self::Item) + Sync + Send,

Mutates each item of this iterator before yielding it. Read more
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fn filter<P>(self, filter_op: P) -> Filter<Self, P>where P: Fn(&Self::Item) -> bool + Sync + Send,

Applies filter_op to each item of this iterator, producing a new iterator with only the items that gave true results. Read more
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fn filter_map<P, R>(self, filter_op: P) -> FilterMap<Self, P>where P: Fn(Self::Item) -> Option<R> + Sync + Send, R: Send,

Applies filter_op to each item of this iterator to get an Option, producing a new iterator with only the items from Some results. Read more
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fn flat_map<F, PI>(self, map_op: F) -> FlatMap<Self, F>where F: Fn(Self::Item) -> PI + Sync + Send, PI: IntoParallelIterator,

Applies map_op to each item of this iterator to get nested iterators, producing a new iterator that flattens these back into one. Read more
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fn reduce<OP, ID>(self, identity: ID, op: OP) -> Self::Itemwhere OP: Fn(Self::Item, Self::Item) -> Self::Item + Sync + Send, ID: Fn() -> Self::Item + Sync + Send,

Reduces the items in the iterator into one item using op. The argument identity should be a closure that can produce “identity” value which may be inserted into the sequence as needed to create opportunities for parallel execution. So, for example, if you are doing a summation, then identity() ought to produce something that represents the zero for your type (but consider just calling sum() in that case). Read more
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fn reduce_with<OP>(self, op: OP) -> Option<Self::Item>where OP: Fn(Self::Item, Self::Item) -> Self::Item + Sync + Send,

Reduces the items in the iterator into one item using op. If the iterator is empty, None is returned; otherwise, Some is returned. Read more
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fn fold<T, ID, F>(self, identity: ID, fold_op: F) -> Fold<Self, ID, F>where F: Fn(T, Self::Item) -> T + Sync + Send, ID: Fn() -> T + Sync + Send, T: Send,

Parallel fold is similar to sequential fold except that the sequence of items may be subdivided before it is folded. Consider a list of numbers like 22 3 77 89 46. If you used sequential fold to add them (fold(0, |a,b| a+b), you would wind up first adding 0 + 22, then 22 + 3, then 25 + 77, and so forth. The parallel fold works similarly except that it first breaks up your list into sublists, and hence instead of yielding up a single sum at the end, it yields up multiple sums. The number of results is nondeterministic, as is the point where the breaks occur. Read more
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fn fold_with<F, T>(self, init: T, fold_op: F) -> FoldWith<Self, T, F>where F: Fn(T, Self::Item) -> T + Sync + Send, T: Send + Clone,

Applies fold_op to the given init value with each item of this iterator, finally producing the value for further use. Read more
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fn try_fold<T, R, ID, F>( self, identity: ID, fold_op: F ) -> TryFold<Self, R, ID, F>where F: Fn(T, Self::Item) -> R + Sync + Send, ID: Fn() -> T + Sync + Send, R: Try<Ok = T> + Send,

Perform a fallible parallel fold. Read more
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fn try_fold_with<F, T, R>(self, init: T, fold_op: F) -> TryFoldWith<Self, R, F>where F: Fn(T, Self::Item) -> R + Sync + Send, R: Try<Ok = T> + Send, T: Clone + Send,

Perform a fallible parallel fold with a cloneable init value. Read more
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fn sum<S>(self) -> Swhere S: Send + Sum<Self::Item> + Sum<S>,

Sums up the items in the iterator. Read more
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fn product<P>(self) -> Pwhere P: Send + Product<Self::Item> + Product<P>,

Multiplies all the items in the iterator. Read more
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fn min_by<F>(self, f: F) -> Option<Self::Item>where F: Sync + Send + Fn(&Self::Item, &Self::Item) -> Ordering,

Computes the minimum of all the items in the iterator with respect to the given comparison function. If the iterator is empty, None is returned; otherwise, Some(min) is returned. Read more
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fn min_by_key<K, F>(self, f: F) -> Option<Self::Item>where K: Ord + Send, F: Sync + Send + Fn(&Self::Item) -> K,

Computes the item that yields the minimum value for the given function. If the iterator is empty, None is returned; otherwise, Some(item) is returned. Read more
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fn max_by<F>(self, f: F) -> Option<Self::Item>where F: Sync + Send + Fn(&Self::Item, &Self::Item) -> Ordering,

Computes the maximum of all the items in the iterator with respect to the given comparison function. If the iterator is empty, None is returned; otherwise, Some(min) is returned. Read more
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fn max_by_key<K, F>(self, f: F) -> Option<Self::Item>where K: Ord + Send, F: Sync + Send + Fn(&Self::Item) -> K,

Computes the item that yields the maximum value for the given function. If the iterator is empty, None is returned; otherwise, Some(item) is returned. Read more
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fn chain<C>(self, chain: C) -> Chain<Self, C::Iter>where C: IntoParallelIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both. Read more
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fn find_any<P>(self, predicate: P) -> Option<Self::Item>where P: Fn(&Self::Item) -> bool + Sync + Send,

Searches for some item in the parallel iterator that matches the given predicate and returns it. This operation is similar to find on sequential iterators but the item returned may not be the first one in the parallel sequence which matches, since we search the entire sequence in parallel. Read more
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fn find_first<P>(self, predicate: P) -> Option<Self::Item>where P: Fn(&Self::Item) -> bool + Sync + Send,

Searches for the sequentially first item in the parallel iterator that matches the given predicate and returns it. Read more
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fn find_last<P>(self, predicate: P) -> Option<Self::Item>where P: Fn(&Self::Item) -> bool + Sync + Send,

Searches for the sequentially last item in the parallel iterator that matches the given predicate and returns it. Read more
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fn find_map_any<P, R>(self, predicate: P) -> Option<R>where P: Fn(Self::Item) -> Option<R> + Sync + Send, R: Send,

Applies the given predicate to the items in the parallel iterator and returns any non-None result of the map operation. Read more
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fn find_map_first<P, R>(self, predicate: P) -> Option<R>where P: Fn(Self::Item) -> Option<R> + Sync + Send, R: Send,

Applies the given predicate to the items in the parallel iterator and returns the sequentially first non-None result of the map operation. Read more
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fn find_map_last<P, R>(self, predicate: P) -> Option<R>where P: Fn(Self::Item) -> Option<R> + Sync + Send, R: Send,

Applies the given predicate to the items in the parallel iterator and returns the sequentially last non-None result of the map operation. Read more
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fn any<P>(self, predicate: P) -> boolwhere P: Fn(Self::Item) -> bool + Sync + Send,

Searches for some item in the parallel iterator that matches the given predicate, and if so returns true. Once a match is found, we’ll attempt to stop process the rest of the items. Proving that there’s no match, returning false, does require visiting every item. Read more
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fn all<P>(self, predicate: P) -> boolwhere P: Fn(Self::Item) -> bool + Sync + Send,

Tests that every item in the parallel iterator matches the given predicate, and if so returns true. If a counter-example is found, we’ll attempt to stop processing more items, then return false. Read more
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fn while_some<T>(self) -> WhileSome<Self>where Self: ParallelIterator<Item = Option<T>>, T: Send,

Creates an iterator over the Some items of this iterator, halting as soon as any None is found. Read more
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fn panic_fuse(self) -> PanicFuse<Self>

Wraps an iterator with a fuse in case of panics, to halt all threads as soon as possible. Read more
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fn collect<C>(self) -> Cwhere C: FromParallelIterator<Self::Item>,

Create a fresh collection containing all the element produced by this parallel iterator. Read more
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fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where Self: ParallelIterator<Item = (A, B)>, FromA: Default + Send + ParallelExtend<A>, FromB: Default + Send + ParallelExtend<B>, A: Send, B: Send,

Unzips the items of a parallel iterator into a pair of arbitrary ParallelExtend containers. Read more
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fn partition<A, B, P>(self, predicate: P) -> (A, B)where A: Default + Send + ParallelExtend<Self::Item>, B: Default + Send + ParallelExtend<Self::Item>, P: Fn(&Self::Item) -> bool + Sync + Send,

Partitions the items of a parallel iterator into a pair of arbitrary ParallelExtend containers. Items for which the predicate returns true go into the first container, and the rest go into the second. Read more
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fn partition_map<A, B, P, L, R>(self, predicate: P) -> (A, B)where A: Default + Send + ParallelExtend<L>, B: Default + Send + ParallelExtend<R>, P: Fn(Self::Item) -> Either<L, R> + Sync + Send, L: Send, R: Send,

Partitions and maps the items of a parallel iterator into a pair of arbitrary ParallelExtend containers. Either::Left items go into the first container, and Either::Right items go into the second. Read more

Auto Trait Implementations§

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impl<T> RefUnwindSafe for Once<T>where T: RefUnwindSafe,

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impl<T> Send for Once<T>

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impl<T> Sync for Once<T>where T: Sync,

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impl<T> Unpin for Once<T>where T: Unpin,

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impl<T> UnwindSafe for Once<T>where T: UnwindSafe,

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoParallelIterator for Twhere T: ParallelIterator,

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type Iter = T

The parallel iterator type that will be created.
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type Item = <T as ParallelIterator>::Item

The type of item that the parallel iterator will produce.
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fn into_par_iter(self) -> T

Converts self into a parallel iterator. Read more
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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.