[Python-checkins] Document differences between random.choices() and random.choice(). (GH-11703)
Raymond Hettinger
webhook-mailer at python.org
Wed Jan 30 16:30:25 EST 2019
https://github.com/python/cpython/commit/40ebe948e97b47fc84c8f527910063286a174b25
commit: 40ebe948e97b47fc84c8f527910063286a174b25
branch: master
author: Raymond Hettinger <rhettinger at users.noreply.github.com>
committer: GitHub <noreply at 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
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