itertools.permutations()
itertools.permutations() is a Python function in the Itertools Module category. Returns all possible r-length ordered arrangements of elements. The syntax is itertools.permutations(iterable, r=None). Parameters: iterable, r (length). Returns: Iterator of tuples. A typical example: list(permutations([1,2,3], 2))
# [(1,2),(1,3),(2,1),(2,3),(3,1),(3,2)]. A close sibling is itertools.chain(), which creates an iterator that returns elements from the first iterable until exhausted, then proceeds to the next. A close sibling is itertools.chain.from_iterable(), which alternative chain that takes a single iterable of iterables. A close sibling is itertools.product(), which cartesian product of input iterables (like nested for-loops). A close sibling is itertools.combinations(), which returns all r-length unordered combinations without replacement. More about this category: Iterator building blocks — chain, product, permutations, combinations, groupby. For a broader walkthrough, read the Itertools Module guide. Related Itertools Module entries: itertools.chain(), itertools.chain.from_iterable(), itertools.product(), itertools.combinations(), itertools.combinations_with_replacement(), itertools.cycle(). This page is part of the free Python Reference documentation covering 978+ functions, methods, and modules with examples and parameter details.