https://github.com/python/cpython/commit/40ebe948e97b47fc84c8f527910063286a1... commit: 40ebe948e97b47fc84c8f527910063286a174b25 branch: master author: Raymond Hettinger <rhettinger@users.noreply.github.com> committer: GitHub <noreply@github.com> date: 2019-01-30T13:30:20-08:00 summary: Document differences between random.choices() and random.choice(). (GH-11703) files: M Doc/library/random.rst diff --git a/Doc/library/random.rst b/Doc/library/random.rst index 4f251574a327..a543ff016a62 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -162,6 +162,13 @@ Functions for sequences with the :class:`float` values returned by :func:`random` (that includes integers, floats, and fractions but excludes decimals). + For a given seed, the :func:`choices` function with equal weighting + typically produces a different sequence than repeated calls to + :func:`choice`. The algorithm used by :func:`choices` uses floating + point arithmetic for internal consistency and speed. The algorithm used + by :func:`choice` defaults to integer arithmetic with repeated selections + to avoid small biases from round-off error. + .. versionadded:: 3.6