Cumulative selection demo (inspired by Richard Dawkins)

weasel.py

#!/usr/bin/env python3

#
# WEASEL
# Inspired by Richard Dawkins.
#

from random import random, choice

genoverse = 'ABCDEFGHIJKLKMNOPQRSTUVWXYZ '
target = list('METHINKS IT IS LIKE A WEASEL')
population = 100
mutability = 0.05
progeny = [choice(genoverse) for _ in target]

generation = 0
while progeny != target:
	individuals = [[choice(list(set(genoverse) - set(g))) if random() <= mutability else g for g in progeny] for _ in range(population)]
	generation += 1
	progeny = max(individuals, key=lambda individual: sum([1 if x == y else 0 for x,y in zip(target, individual)]))
	print("{}:\t{}".format(generation, ''.join(progeny)))