weighted choice

gistfile1.py

from random import random

class thing:
    def __init__(self, value, weight=1):
        self.value = value
        self.weight = weight

    def __str__(self):
        return str(self.value) + ' ' + str(self.weight)


things = [thing(x) for x in range(10)]

def pick():
    total_weight = sum(map(lambda thing: thing.weight, things))
    choice_weight = total_weight*random()
    chosen = None
    i = 0

    while choice_weight > 0:
        chosen = things[i]
        choice_weight -= chosen.weight
        i += 1

    chosen_weight[chosen.weight] += 1
    chosen.weight /= 10

    for th in things:
        th.weight += 1

    return chosen

chosen = [0]*10

chosen_weight = [0]*100

for _ in range(1000000):
    ch = pick()
    chosen[ch.value] += 1
    diff = max(chosen) - min(chosen)
    print diff
for c in range(100):
    print c, chosen_weight[c]

print chosen