#coding: utf-8

import os
from itertools import groupby

file_lst = []
for path, dir, files in os.walk('./'):
    file_lst += files

file_count = len(file_lst) * 1.0

for key, lst in groupby(file_lst, key=lambda x: os.path.splitext(x)[1]):
    print key, round(len(list(lst))/file_count, 2)

看第二种：

#coding: utf-8

import os
from collections import defaultdict

file_count = 1.0
res = defaultdict()
for path, dir, files in os.walk('./'):
    file_count += len(files)
    for file in files:
        suf = os.path.splitext(file)[1]
        res[suf] = res.setdefault(suf, 0) + 1

for k, v in res.iteritems():
    print k, round(v/file_count, 4) * 100

改进后的

# coding: utf-8

import os
from itertools import groupby


def getpercent(num):
    return str(round(num / file_count * 100, 2))


def getresult():
    for key in language_dict:
        print '%s count:%d  percent:%s%%' % (key, language_dict.get(key), getpercent(language_dict[key]))


if __name__ == '__main__':
    file_lst = []
    language_dict = {}
    for path, dirs, files in os.walk('./'):
        file_lst += files

    file_count = len(file_lst) * 1.0

    for key, lst in groupby(file_lst, key=lambda x: os.path.splitext(x)[1]):
        if key not in language_dict.keys():
            language_dict[key] = len(list(lst))
        else:
            language_dict[key] = language_dict.get(key) + len(list(lst))

    getresult()