all Python 3itertoolsfunction

itertools.count

itertools

An infinite counter: start, start+step, …

Syntax

itertools.count(start=0, step=1)

The counter is infinite: list(count()) or a for-loop without a break will hang and exhaust memory — bound it with islice(), zip(), or takewhile(). A common use is as an index generator paired with zip() (enumerate-style), and step may be a float.

Examples

import itertools
c = itertools.count(10)
print(next(c), next(c), next(c))   # → 10 11 12
print(list(itertools.islice(itertools.count(0, 5), 4)))   # → [0, 5, 10, 15]
print(list(zip(itertools.count(1), 'abc')))   # → [(1, 'a'), (2, 'b'), (3, 'c')]
print(list(itertools.islice(itertools.count(3, -1), 5)))   # → [3, 2, 1, 0, -1]

See also

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