Stochastic measure of the sortedness of a list

stochastic_sortedness.py

import random


def stochastic_sortedness(list_, num_samples):
    ''' Based on https://stackoverflow.com/a/16994740/643675 '''
    if len(list_) < 2:
        return 0
    # a 2 item list works, but is a pretty dumb thing to pass to this function *shrug*
    maxindex = len(list_) - 1 
    score = 0
    count = 0
    while count < num_samples:
        i1 = random.randint(0, maxindex)
        i2 = random.randint(0, maxindex)
        if i1 != i2:
            score += 0 if list_[min(i1, i2)] <= list_[max(i1, i2)] else 1
            count += 1
    return score / num_samples