1.0.0[][src]Trait tract_tensorflow::prelude::tract_itertools::__std_iter::ExactSizeIterator

pub trait ExactSizeIterator: Iterator {
    pub fn len(&self) -> usize { ... }
pub fn is_empty(&self) -> bool { ... } }

An iterator that knows its exact length.

Many Iterators don't know how many times they will iterate, but some do. If an iterator knows how many times it can iterate, providing access to that information can be useful. For example, if you want to iterate backwards, a good start is to know where the end is.

When implementing an ExactSizeIterator, you must also implement Iterator. When doing so, the implementation of Iterator::size_hint must return the exact size of the iterator.

The len method has a default implementation, so you usually shouldn't implement it. However, you may be able to provide a more performant implementation than the default, so overriding it in this case makes sense.

Examples

Basic usage:

// a finite range knows exactly how many times it will iterate
let five = 0..5;

assert_eq!(5, five.len());

In the module-level docs, we implemented an Iterator, Counter. Let's implement ExactSizeIterator for it as well:

impl ExactSizeIterator for Counter {
    // We can easily calculate the remaining number of iterations.
    fn len(&self) -> usize {
        5 - self.count
    }
}

// And now we can use it!

let counter = Counter::new();

assert_eq!(5, counter.len());

Provided methods

pub fn len(&self) -> usize[src]

Returns the exact length of the iterator.

The implementation ensures that the iterator will return exactly len() more times a Some(T) value, before returning None. This method has a default implementation, so you usually should not implement it directly. However, if you can provide a more efficient implementation, you can do so. See the trait-level docs for an example.

This function has the same safety guarantees as the Iterator::size_hint function.

Examples

Basic usage:

// a finite range knows exactly how many times it will iterate
let five = 0..5;

assert_eq!(5, five.len());

pub fn is_empty(&self) -> bool[src]

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

Returns true if the iterator is empty.

This method has a default implementation using ExactSizeIterator::len(), so you don't need to implement it yourself.

Examples

Basic usage:

#![feature(exact_size_is_empty)]

let mut one_element = std::iter::once(0);
assert!(!one_element.is_empty());

assert_eq!(one_element.next(), Some(0));
assert!(one_element.is_empty());

assert_eq!(one_element.next(), None);
Loading content...

Implementations on Foreign Types

impl<K, V> ExactSizeIterator for IntoValues<K, V>[src]

impl<'_, K, V> ExactSizeIterator for ValuesMut<'_, K, V>[src]

impl<K, V> ExactSizeIterator for IntoKeys<K, V>[src]

impl<'_, K, V> ExactSizeIterator for Values<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for Iter<'_, K, V>[src]

impl<'_, K> ExactSizeIterator for Iter<'_, K>[src]

impl<K, V> ExactSizeIterator for IntoIter<K, V>[src]

impl<'_, K> ExactSizeIterator for Drain<'_, K>[src]

impl<K> ExactSizeIterator for IntoIter<K>[src]

impl<'a> ExactSizeIterator for CommandEnvs<'a>[src]

impl ExactSizeIterator for ArgsOs[src]

impl<'_, K, V> ExactSizeIterator for Drain<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for IterMut<'_, K, V>[src]

impl<'a> ExactSizeIterator for CommandArgs<'a>[src]

impl<'_, K, V> ExactSizeIterator for Keys<'_, K, V>[src]

impl ExactSizeIterator for Args[src]

impl ExactSizeIterator for Range<u8>[src]

impl ExactSizeIterator for Range<u16>[src]

impl<'_, A> ExactSizeIterator for Iter<'_, A>[src]

impl<'_, I> ExactSizeIterator for &'_ mut I where
    I: ExactSizeIterator + ?Sized
[src]

impl ExactSizeIterator for RangeInclusive<u16>[src]

impl ExactSizeIterator for ToLowercase[src]

impl ExactSizeIterator for Range<isize>[src]

impl ExactSizeIterator for Range<i32>[src]

impl<A> ExactSizeIterator for IntoIter<A>[src]

impl<'_, T> ExactSizeIterator for IterMut<'_, T>[src]

impl ExactSizeIterator for ToUppercase[src]

impl ExactSizeIterator for EscapeDebug[src]

impl ExactSizeIterator for Range<i8>[src]

impl ExactSizeIterator for EscapeUnicode[src]

impl ExactSizeIterator for RangeInclusive<i8>[src]

impl ExactSizeIterator for RangeInclusive<u8>[src]

impl ExactSizeIterator for Range<usize>[src]

impl<'_, T> ExactSizeIterator for Iter<'_, T>[src]

impl ExactSizeIterator for Range<u32>[src]

impl<T, const N: usize> ExactSizeIterator for IntoIter<T, N>[src]

impl ExactSizeIterator for EscapeDefault[src]

impl<T> ExactSizeIterator for IntoIter<T>[src]

impl ExactSizeIterator for EscapeDefault[src]

impl ExactSizeIterator for Range<i16>[src]

impl ExactSizeIterator for RangeInclusive<i16>[src]

impl<'_, A> ExactSizeIterator for IterMut<'_, A>[src]

impl<T> ExactSizeIterator for IntoIter<T> where
    T: Buf
[src]

impl<B> ExactSizeIterator for IntoIter<B> where
    B: BitBlock
[src]

impl<'a, B> ExactSizeIterator for Blocks<'a, B> where
    B: BitBlock
[src]

impl<'a, B> ExactSizeIterator for Iter<'a, B> where
    B: BitBlock
[src]

impl<I> ExactSizeIterator for ExactlyOneError<I> where
    I: ExactSizeIterator
[src]

impl<A> ExactSizeIterator for Zip<(A,)> where
    A: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Step<I> where
    I: ExactSizeIterator
[src]

impl<I, F> ExactSizeIterator for PadUsing<I, F> where
    I: ExactSizeIterator,
    F: FnMut(usize) -> <I as Iterator>::Item
[src]

impl<I, F> ExactSizeIterator for Update<I, F> where
    I: ExactSizeIterator,
    F: FnMut(&mut <I as Iterator>::Item), 
[src]

impl<A, B> ExactSizeIterator for Zip<(A, B)> where
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<I, R> ExactSizeIterator for MapInto<I, R> where
    I: ExactSizeIterator,
    <I as Iterator>::Item: Into<R>, 
[src]

impl<A, B, C, D, E> ExactSizeIterator for Zip<(A, B, C, D, E)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator
[src]

impl<T> ExactSizeIterator for TupleBuffer<T> where
    T: TupleCollect, 
[src]

impl<A, B, C, D, E, F, G> ExactSizeIterator for Zip<(A, B, C, D, E, F, G)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator,
    G: ExactSizeIterator
[src]

impl<T, U> ExactSizeIterator for ZipLongest<T, U> where
    T: ExactSizeIterator,
    U: ExactSizeIterator
[src]

impl<A, B, C> ExactSizeIterator for Zip<(A, B, C)> where
    C: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for WithPosition<I> where
    I: ExactSizeIterator
[src]

impl<A, B, C, D, E, F> ExactSizeIterator for Zip<(A, B, C, D, E, F)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator
[src]

impl<I, J> ExactSizeIterator for ZipEq<I, J> where
    I: ExactSizeIterator,
    J: ExactSizeIterator
[src]

impl<A, B, C, D> ExactSizeIterator for Zip<(A, B, C, D)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<A, B, C, D, E, F, G, H> ExactSizeIterator for Zip<(A, B, C, D, E, F, G, H)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    H: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator,
    G: ExactSizeIterator
[src]

impl<A> ExactSizeIterator for RepeatN<A> where
    A: Clone
[src]

impl<'a, A> ExactSizeIterator for Drain<'a, A> where
    A: Array,
    <A as Array>::Item: 'a, 
[src]

impl<A> ExactSizeIterator for IntoIter<A> where
    A: Array
[src]

Loading content...

Implementors

impl<'_> ExactSizeIterator for Chain<'_>[src]

impl<'_> ExactSizeIterator for Bytes<'_>[src]

impl<'_, I, A> ExactSizeIterator for Splice<'_, I, A> where
    I: Iterator,
    A: Allocator
[src]

impl<'_, K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::Iter<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::IterMut<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::Keys<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::Values<'_, K, V>[src]

impl<'_, K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::ValuesMut<'_, K, V>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::binary_heap::Drain<'_, T>[src]

impl<'_, T> ExactSizeIterator for DrainSorted<'_, T> where
    T: Ord
[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::binary_heap::Iter<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_set::Iter<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::linked_list::Iter<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::linked_list::IterMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::vec_deque::Drain<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::vec_deque::Iter<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::vec_deque::IterMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for Chunks<'_, T>[src]

impl<'_, T> ExactSizeIterator for ChunksExact<'_, T>[src]

impl<'_, T> ExactSizeIterator for ChunksExactMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for ChunksMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::slice::Iter<'_, T>[src]

impl<'_, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::slice::IterMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for RChunks<'_, T>[src]

impl<'_, T> ExactSizeIterator for RChunksExactMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for RChunksMut<'_, T>[src]

impl<'_, T> ExactSizeIterator for Windows<'_, T>[src]

impl<'_, T, A> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::vec::Drain<'_, T, A> where
    A: Allocator
[src]

impl<'_, T, const N: usize> ExactSizeIterator for ArrayChunks<'_, T, N>[src]

impl<'_, T, const N: usize> ExactSizeIterator for ArrayChunksMut<'_, T, N>[src]

impl<'_, T, const N: usize> ExactSizeIterator for ArrayWindows<'_, T, N>[src]

impl<'a, A, D> ExactSizeIterator for AxisChunksIter<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for AxisChunksIterMut<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for AxisIter<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for AxisIterMut<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for IndexedIter<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for IndexedIterMut<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for tract_tensorflow::prelude::tract_ndarray::iter::Iter<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for tract_tensorflow::prelude::tract_ndarray::iter::IterMut<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for LanesIter<'a, A, D> where
    D: Dimension
[src]

impl<'a, A, D> ExactSizeIterator for LanesIterMut<'a, A, D> where
    D: Dimension
[src]

impl<'a, I, T> ExactSizeIterator for Cloned<I> where
    T: 'a + Clone,
    I: ExactSizeIterator<Item = &'a T>, 
[src]

impl<'a, I, T> ExactSizeIterator for Copied<I> where
    T: 'a + Copy,
    I: ExactSizeIterator<Item = &'a T>, 
[src]

impl<'a, T> ExactSizeIterator for RChunksExact<'a, T>[src]

impl<'a, T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::Drain<'a, T> where
    T: Array

impl<A> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::IntoIter<A> where
    A: Array

impl<A> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::RepeatN<A> where
    A: Clone
[src]

impl<A> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A,)> where
    A: ExactSizeIterator
[src]

impl<A, B> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::__std_iter::Zip<A, B> where
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<A, B> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B)> where
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<A, B, C> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C)> where
    C: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<A, B, C, D> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C, D)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator
[src]

impl<A, B, C, D, E> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C, D, E)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator
[src]

impl<A, B, C, D, E, F> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C, D, E, F)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator
[src]

impl<A, B, C, D, E, F, G> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C, D, E, F, G)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator,
    G: ExactSizeIterator
[src]

impl<A, B, C, D, E, F, G, H> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Zip<(A, B, C, D, E, F, G, H)> where
    C: ExactSizeIterator,
    D: ExactSizeIterator,
    B: ExactSizeIterator,
    F: ExactSizeIterator,
    H: ExactSizeIterator,
    A: ExactSizeIterator,
    E: ExactSizeIterator,
    G: ExactSizeIterator
[src]

impl<A, F> ExactSizeIterator for OnceWith<F> where
    F: FnOnce() -> A, 
[src]

impl<B, I, F> ExactSizeIterator for Map<I, F> where
    I: ExactSizeIterator,
    F: FnMut(<I as Iterator>::Item) -> B, 
[src]

impl<D> ExactSizeIterator for IndicesIter<D> where
    D: Dimension
[src]

impl<I> ExactSizeIterator for Enumerate<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Fuse<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Peekable<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Rev<I> where
    I: ExactSizeIterator + DoubleEndedIterator
[src]

impl<I> ExactSizeIterator for Skip<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for StepBy<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Take<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::ExactlyOneError<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for MultiPeek<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Step<I> where
    I: ExactSizeIterator
[src]

impl<I> ExactSizeIterator for Tee<I> where
    I: ExactSizeIterator,
    <I as Iterator>::Item: Clone
[src]

impl<I> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::WithPosition<I> where
    I: ExactSizeIterator
[src]

impl<I, A> ExactSizeIterator for Box<I, A> where
    I: ExactSizeIterator + ?Sized,
    A: Allocator
[src]

impl<I, F> ExactSizeIterator for Inspect<I, F> where
    I: ExactSizeIterator,
    F: FnMut(&<I as Iterator>::Item), 
[src]

impl<I, F> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::PadUsing<I, F> where
    I: ExactSizeIterator,
    F: FnMut(usize) -> <I as Iterator>::Item
[src]

impl<I, F> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::Update<I, F> where
    I: ExactSizeIterator,
    F: FnMut(&mut <I as Iterator>::Item), 
[src]

impl<I, J> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::ZipEq<I, J> where
    I: ExactSizeIterator,
    J: ExactSizeIterator
[src]

impl<I, R> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::MapInto<I, R> where
    I: ExactSizeIterator,
    <I as Iterator>::Item: Into<R>, 
[src]

impl<K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::IntoIter<K, V>[src]

impl<K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::IntoKeys<K, V>[src]

impl<K, V> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_map::IntoValues<K, V>[src]

impl<L, R> ExactSizeIterator for Either<L, R> where
    R: ExactSizeIterator<Item = <L as Iterator>::Item>,
    L: ExactSizeIterator
[src]

impl<T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::binary_heap::IntoIter<T>[src]

impl<T> ExactSizeIterator for IntoIterSorted<T> where
    T: Ord
[src]

impl<T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::btree_set::IntoIter<T>[src]

impl<T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::linked_list::IntoIter<T>[src]

impl<T> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::collections::vec_deque::IntoIter<T>[src]

impl<T> ExactSizeIterator for Empty<T>[src]

impl<T> ExactSizeIterator for Once<T>[src]

impl<T> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::TupleBuffer<T> where
    T: HomogeneousTuple
[src]

impl<T, A> ExactSizeIterator for tract_tensorflow::prelude::tract_data::internal::tract_smallvec::alloc::vec::IntoIter<T, A> where
    A: Allocator
[src]

impl<T, U> ExactSizeIterator for tract_tensorflow::prelude::tract_itertools::ZipLongest<T, U> where
    T: ExactSizeIterator,
    U: ExactSizeIterator
[src]

Loading content...