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Issue #18844: Make the various ways for specifing weights produce the same results.

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This commit is contained in:
Raymond Hettinger 2016-10-29 16:55:36 -07:00
parent ab5cf4da4e
commit 30d00e54dd
3 changed files with 23 additions and 3 deletions
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7
Lib/random.py
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@ -344,10 +344,12 @@ class Random(_random.Random):
the selections are made with equal probability.
"""
random = self.random
if cum_weights is None:
if weights is None:
choice = self.choice
return [choice(population) for i in range(k)]
_int = int
total = len(population)
return [population[_int(random() * total)] for i in range(k)]
else:
cum_weights = list(_itertools.accumulate(weights))
elif weights is not None:
@ -355,7 +357,6 @@ class Random(_random.Random):
if len(cum_weights) != len(population):
raise ValueError('The number of weights does not match the population')
bisect = _bisect.bisect
random = self.random
total = cum_weights[-1]
return [population[bisect(cum_weights, random() * total)] for i in range(k)]