itertools

..
Basic	Basic iterables.
ChainIterator	An iterator that chains two iterators one after the other.
CountIterator	An iterator that counts up integers.
EmptyIterator	A simple empty iterator that returns nothing.
EnumerateIterator	An iterator that includes the index for each element.
Extensions	Extension functions to provide a fluent iterator API. Use with:
FilterIterator	An iterator that keeps elements based on a predicate.
FlattenIterator	An iterator that flattens an iterator of iterators.
FuncIterable	An iterable based on a function to create the iterator.
GroupByIterator	An iterator that groups elements by a key.
Grouping	A single grouping.
Indexed	A pair of index and element.
IteratorException	The exception thrown when something fatal happens during iteration.
MapIterator	An iterator that transforms each element with a given function.
OnceIterable	An iterable that can only be used once.
Pair	A pair of zipped elements.
RepeatIterator	An iterator that repeats a single element infinitely.
ReverseIterator	An iterator that goes in reverse order.
ScanlIterator	An iterator that applies a reduction each step, accumulating the results.
SkipIterator	An iterator that skips the first n elements.
SkipWhileIterator	An iterator that skips elements as long as a predicate is true.
TakeIterator	An iterator that takes the first n elements.
TakeWhileIterator	An iterator that takes elements as long as a predicate is true.
ZipIterator	An iterator making a pair iterator from two other iterators.