[New-bugs-announce] [issue31689] random.choices does not work with negative weights

[Allen Riddell]

New submission from Allen Riddell <abr at ariddell.org>:

Code to reproduce problem:

population = list(range(10))
weights = list(-1 * w for w in range(10))
[random.choices(population, weights) for _ in range(1000)]

will raise IndexError:

    358         bisect = _bisect.bisect
    359         total = cum_weights[-1]
--> 360         return [population[bisect(cum_weights, random() * total)] for i in range(k)]
    361 
    362 ## -------------------- real-valued distributions  -------------------

IndexError: list index out of range

----------
components: Library (Lib)
messages: 303683
nosy: ariddell
priority: normal
severity: normal
status: open
title: random.choices does not work with negative weights
versions: Python 3.6

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31689>
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