关于根据元素的权重选择随机元素的 Python 算法

[Livid]

http://eli.thegreenplace.net/2010/01/22/weighted-random-generation-in-python/

Love this fast and elegant one.

class WeightedRandomGenerator(object):
    def __init__(self, weights):
        self.totals = []
        running_total = 0

        for w in weights:
            running_total += w
            self.totals.append(running_total)

    def next(self):
        rnd = random.random() * self.totals[-1]
        return bisect.bisect_right(self.totals, rnd)

    def __call__(self):
        return self.next()

[mengzhuo]

前段时间考察过这个算法，在总量小的情况下（<1000）
用Python自带的for 循环比 bisect效率高

[koykoi]

Roulette Wheel

[qiukun]

@mengzhuo 感人。。

[efi]

numpy.random.choice(1, p=weights)