This commit is contained in:
Raymond Hettinger 2016-09-05 13:15:20 -07:00
commit c7fac12f19
1 changed files with 6 additions and 0 deletions

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@ -329,6 +329,9 @@ population with repeats::
>>> weighted_choices = [('Red', 3), ('Blue', 2), ('Yellow', 1), ('Green', 4)]
>>> population = [val for val, cnt in weighted_choices for i in range(cnt)]
>>> population
['Red', 'Red', 'Red', 'Blue', 'Blue', 'Yellow', 'Green', 'Green', 'Green', 'Green']
>>> random.choice(population)
'Green'
@ -338,6 +341,9 @@ with :func:`itertools.accumulate`, and then locate the random value with
>>> choices, weights = zip(*weighted_choices)
>>> cumdist = list(itertools.accumulate(weights))
>>> cumdist # [3, 3+2, 3+2+1, 3+2+1+4]
[3, 5, 6, 10]
>>> x = random.random() * cumdist[-1]
>>> choices[bisect.bisect(cumdist, x)]
'Blue'