Raymond Hettinger <raymond.hettin...@gmail.com> added the comment:
This is known and an intentional design decision. It isn't just a speed issue.
Because the weights can be floats, we have floats involved at the outset and
some round-off is unavoidable. To keep the method internally consistent, the
same technique is used even when the weights aren't specified:
>>> from random import choices, seed
>>> seed(8675309**3)
>>> s = choices('abcdefg', k=20)
>>> seed(8675309**3)
>>> t = choices('abcdefg', [0.7] * 7, k=20)
>>> s == t
True
FWIW, this is documented:
"""
For a given seed, the choices() function with equal weighting typically
produces a different sequence than repeated calls to choice(). The algorithm
used by choices() uses floating point arithmetic for internal consistency and
speed. The algorithm used by choice() defaults to integer arithmetic with
repeated selections to avoid small biases from round-off error.
"""
----------
assignee: -> rhettinger
resolution: -> not a bug
stage: -> resolved
status: open -> closed
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue44080>
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