itertools.combinations
Iterate over combinations: groups of r items regardless of order.
Python 3.13
itertools.combinations(iterable, r)Parameters
- iterableIterable
- The items to combine.
- rint
- How many items are in one combination.
Return value
An iterator of tuples in the order of the original items.
Examples
Combinations of two items
Python 3.13
from itertools import combinations
print(list(combinations('abc', 2)))[('a', 'b'), ('a', 'c'), ('b', 'c')]Pairs of numbers that add up to 10
Python 3.13
from itertools import combinations
numbers = [2, 8, 5, 5, 3]
print([pair for pair in combinations(numbers, 2) if sum(pair) == 10])[(2, 8), (5, 5)]
Details
Order does not matter: of (a, b) and (b, a), only the first is produced. Combinations with repeated items are given by itertools.combinations_with_replacement. If r is greater than the number of items, the result is empty.