Python Weighted Random

python algorithm round-robin
doremi picture doremi · Feb 21, 2013 · Viewed 52.5k times · Source

I need to return different values based on a weighted round-robin such that 1 in 20 gets A, 1 in 20 gets B, and the rest go to C.

So:

A => 5%
B => 5%
C => 90%

Here's a basic version that appears to work:

import random

x = random.randint(1, 100)

if x <= 5:
    return 'A'
elif x > 5 and x <= 10:
    return 'B'
else:
    return 'C'

Is this algorithm correct? If so, can it be improved?

Answer

jurgenreza picture jurgenreza · Feb 21, 2013

Your algorithm is correct, how about something more elegant:

import random
my_list = ['A'] * 5 + ['B'] * 5 + ['C'] * 90
random.choice(my_list)

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