看不懂的genetic-algorithm ，推荐一本书 《genetic-algorithm-with-python》

此书我才看了没几页。但是其中的代码实在是精妙，不由顿生不明觉厉的感慨。
最早的版本是数据和算法混合在一起的代码：

import string
import random

geneSet=string.ascii_letters+" !?.,"
target="Hello World!"

def generate_parent(length):
    genes=[]
    while len(genes) < length:
        sampleSize=min((length - len(genes)), len(geneSet))
        genes.extend(random.sample(geneSet, sampleSize))
    return ''.join(genes)


#print(generate_parent(10))

def get_fitness(guess):
    return sum(1 for expected, actual in zip(target, guess) if expected == actual)

def mutate(parent):
    index=random.randrange(0,len(parent))
    childGenes=list(parent)
    newGene, alternate=random.sample(geneSet, 2)
    childGenes[index]=alternate if newGene ==childGenes[index] else newGene
    return ''.join(childGenes)


import datetime

def display(guess):
    timeDiff=datetime.datetime.now() - startTime
    fitness=get_fitness(guess)
    print("{0}\t{1}\t{2}".format(guess, fitness, str(timeDiff)))


random.seed()
startTime=datetime.datetime.now()
bestParent=generate_parent(len(target))
bestFitness=get_fitness(bestParent)
display(bestParent)

while True:
    child=mutate(bestParent)
    childFitness=get_fitness(child)
    if bestFitness >= childFitness:
        continue
    display(child)
    if childFitness >= len(bestParent):
        break
    bestFitness=childFitness
    bestParent=child

然后第二个版本是讲算法单独抽出来做了个genetic.py.
将实际的应用写入guesspassword.py

genetic.py 如下：

import random

def _generate_parent(length, geneSet):
    genes=[]
    while len(genes) < length:
        sampleSize=min(length-len(genes), len(geneSet))
        genes.extend(random.sample(geneSet, sampleSize))
    return ''.join(genes)

def _mutate(parent, geneSet):
    index=random.randrange(0, len(parent))
    childGenes=list(parent)
    newGene, alternate=random.sample(geneSet, 2)
    if newGene==childGenes[index]:
        childGenes[index]=alternate
    else:
        childGenes[index]=newGene

    return ''.join(childGenes)


def get_best(get_fitness, targetLen, optimalFitness, geneSet, display):
    random.seed()
    bestParent=_generate_parent(targetLen, geneSet)
    bestFitness=get_fitness(bestParent)
    display(bestParent)

    if bestFitness >= optimalFitness:
        return bestParent

    while True:
        child=_mutate(bestParent, geneSet)
        childFitness = get_fitness(child)
        if bestFitness >= childFitness:
            continue

        display(child)
        if childFitness >= optimalFitness:
            return child
        bestFitness = childFitness
        bestParent=child

guesspassword.py 内容如下：

import datetime
import genetic
import string
import unittest

def test_hello_world():
    target="Hello World!"
    guess_password(target)

def guess_password(target):
    geneset=string.ascii_letters+" !?.,"
    startTime=datetime.datetime.now()

    def fnGetFitness(genes):
        return get_fitness(genes,target)

    def fnDisplay(genes):
        display(genes, target, startTime)

    optimalFitness=len(target)
    genetic.get_best(fnGetFitness, len(target), optimalFitness, geneset, fnDisplay)

def display(genes, target, startTime):
    timeDiff=datetime.datetime.now() - startTime
    fitness= get_fitness(genes, target)
    print("{0}\t{1}\t{2}".format(genes, fitness, str(timeDiff)))

def get_fitness(genes, target):
    return sum( 1 for expected, actual in zip(target, genes) if expected==actual)


#test_hello_world()


    def fnDisplay(genes):
        display(genes, target, startTime)

class GuessPasswordTests(unittest.TestCase):
    geneset=string.ascii_letters+" !?,."
    startTime=datetime.datetime.now()

    def test_001_hello_world(self):
        target="Hello World!"
        self.guess_password(target)

    def guess_password(self, target):
        def fnGetFitness(genes):
            return get_fitness(genes,target)

        def fnDisplay(genes):
            display(genes, target, self.startTime)

        optimalFitness=len(target)
        best=genetic.get_best(fnGetFitness, len(target), optimalFitness, self.geneset, fnDisplay)
        self.assertEqual(best, target)


    def test_002_for_i_am_fearfully_and_wonderfully_made(self):
        target="For I am fearfully and wonderfully made."
        self.guess_password(target)

unittest.main()

后记：

因为书上用了statistics 这个library,害得我在kali 上找了半天，不知道为啥官方源把我定向到kali.mirror.garr.it，超级慢，apt-get update 要跑3天。
还是改了好。 

#中科大kali source
deb http://mirrors.ustc.edu.cn/kali kali-rolling main contrib non-free
deb-src http://mirrors.ustc.edu.cn/kali kali-rolling main contrib non-free

瞎猜一通，感觉astlib 像是，最后还给我蒙对了

apt-cache search statistics |grep -i python3
apt-get install astlib

>>> import statistics
>>> statistics.__file__
'/usr/lib/python3.5/statistics.py'
>>> statistics.__name__
'statistics'