itertools.permutations
Iterate over the permutations of items, all possible orders.
Python 3.13
itertools.permutations(iterable, r=None)Parameters
- iterableIterable
- The items to permute.
- rint | Noneoptional
- The length of a permutation; all items by default.
Return value
An iterator of tuples.
Examples
Permutations of two items
Python 3.13
from itertools import permutations
print(list(permutations('abc', 2)))[('a', 'b'), ('a', 'c'), ('b', 'a'), ('b', 'c'), ('c', 'a'), ('c', 'b')]Number of permutations of four
Python 3.13
from itertools import permutations
print(len(list(permutations(range(4)))))24
Details
Order matters: (a, b) and (b, a) are different permutations. Items are distinguished by position, not by value, so repeated items give identical tuples. Without r there are n! permutations, and their number grows quickly.