all Python 3functoolsterm

functools

module

Higher-order functions: caching results, partial application, folding, decorator wrappers and dispatch on type.

Syntax

from functools import lru_cache, partial

functools is a toolkit for functions: lru_cache and cache remember results, partial fixes some arguments, wraps keeps the name and docstring of a decorated function. Ready-made iterators live next door, in itertools. The cache stores arguments as dictionary keys, so they must be hashable: a list argument raises TypeError.

Examples

from functools import lru_cache, reduce
@lru_cache(maxsize=None)
def fib(n):
    return n if n < 2 else fib(n - 1) + fib(n - 2)
print(fib(80))  # → 23416728348467685
print(reduce(lambda a, b: a * b, [1, 2, 3, 4]))  # → 24

See also

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