是否替换嵌套的循环... [英] Replace Nested For Loops... or not

问题描述

我有一个脚本，该脚本循环遍历四个(或更少)字符串.例如:

I have a script that loops through a series of four (or less) characters strings. For example:

aaaa
aaab
aaac
aaad

如果能够使用嵌套的for循环来实现它，就像这样:

If have been able to implement it with nested for loops like so:

chars = string.digits + string.uppercase + string.lowercase

for a in chars:
    print '%s' % a   
    for b in chars:
        print '%s%s' % (a, b)
        for c in chars:
            print '%s%s%s' % (a, b, c)
            for d in chars:
                print '%s%s%s%s' % (a, b, c, d)

这种循环嵌套不好吗?如果是的话，哪种方法可以更好地完成我的工作?

Is this sort of loop nesting a bad thing, and if so, what would be a better way of accomplishing what I am doing?

推荐答案

import string
import itertools

chars = string.digits + string.letters
MAX_CHARS = 4
for nletters in range(MAX_CHARS):
    for word in itertools.product(chars, repeat=nletters + 1):
        print (''.join(word))

这将打印您要查找的所有 15018570 单词.如果您想要更多/更少的单词，只需更改 MAX_CHARS 变量.对于任何数量的字符，它仍然只有两个 for ，并且您不必重复自己的操作.并且可读性强.

That'll print all 15018570 words you're looking for. If you want more/less words just change the MAX_CHARS variable. It will still have just two fors for any number of chars, and you don't have to repeat yourself. And is pretty readable. .

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