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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2019-11-23 10:22:13 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-11-23 10:22:13 (GMT) |
| commit | 041d8b48a2e59fa642b2c5124d78086baf74e339 (patch) | |
| tree | f189a49ce0107fdeef9eeb75e9e6c63fb169e83c /Doc | |
| parent | 84b1ff65609c5910b4f838adbe1ead83baae7dbf (diff) | |
| download | cpython-041d8b48a2e59fa642b2c5124d78086baf74e339.zip cpython-041d8b48a2e59fa642b2c5124d78086baf74e339.tar.gz cpython-041d8b48a2e59fa642b2c5124d78086baf74e339.tar.bz2 | |
bpo-38881: choices() raises ValueError when all weights are zero (GH-17362)
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/random.rst | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Doc/library/random.rst b/Doc/library/random.rst index 1bd1856..933da3f 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -165,8 +165,9 @@ Functions for sequences The *weights* or *cum_weights* can use any numeric type that interoperates with the :class:`float` values returned by :func:`random` (that includes - integers, floats, and fractions but excludes decimals). Weights are - assumed to be non-negative. + integers, floats, and fractions but excludes decimals). Behavior is + undefined if any weight is negative. A :exc:`ValueError` is raised if all + weights are zero. For a given seed, the :func:`choices` function with equal weighting typically produces a different sequence than repeated calls to @@ -177,6 +178,9 @@ Functions for sequences .. versionadded:: 3.6 + .. versionchanged:: 3.9 + Raises a :exc:`ValueError` if all weights are zero. + .. function:: shuffle(x[, random]) |