Trait core::iter::ExactSizeIteratorUnstable

pub trait ExactSizeIterator<A>: DoubleEndedIterator<A> {
    fn rposition<P>(&mut self, predicate: P) -> Option<uint> where P: FnMut(A) -> bool { ... }
    fn len(&self) -> uint { ... }
}

An iterator that knows its exact length

This trait is a helper for iterators like the vector iterator, so that it can support double-ended enumeration.

Iterator::size_hint must return the exact size of the iterator. Note that the size must fit in uint.

Provided Methods

fn rposition<P>(&mut self, predicate: P) -> Option<uint> where P: FnMut(A) -> bool

Return the index of the last element satisfying the specified predicate

If no element matches, None is returned.

fn len(&self) -> uint

Return the exact length of the iterator.

Implementors

• impl<Idx: Clone + Step> ExactSizeIterator<Idx> for Range<Idx>
• impl<A, T: ExactSizeIterator<A>> ExactSizeIterator<(uint, A)> for Enumerate<T>
• impl<A, I, F> ExactSizeIterator<A> for Inspect<A, I, F> where I: ExactSizeIterator<A>, F: FnMut(&A)
• impl<A, T: ExactSizeIterator<A>> ExactSizeIterator<A> for Rev<T>
• impl<A, B, I, F> ExactSizeIterator<B> for Map<A, B, I, F> where I: ExactSizeIterator<A>, F: FnMut(A) -> B
• impl<A, B, T, U> ExactSizeIterator<(A, B)> for Zip<T, U> where T: ExactSizeIterator<A>, U: ExactSizeIterator<B>
• impl<A: Clone, D: Deref<A>, I: ExactSizeIterator<D>> ExactSizeIterator<A> for Cloned<I>
• impl<'a, A> ExactSizeIterator<&'a A> for Iter<'a, A>
• impl<'a, A> ExactSizeIterator<&'a mut A> for IterMut<'a, A>
• impl<A> ExactSizeIterator<A> for IntoIter<A>
• impl<'a, T> ExactSizeIterator<&'a T> for Iter<'a, T>
• impl<'a, T> ExactSizeIterator<&'a mut T> for IterMut<'a, T>
• impl<T> ExactSizeIterator<T> for IntoIter<T>
• impl<'a, T> ExactSizeIterator<&'a T> for Iter<'a, T>
• impl<'a, T> ExactSizeIterator<&'a mut T> for IterMut<'a, T>
• impl<'a> ExactSizeIterator<u8> for Bytes<'a>