python 批量给数字前面补0

import re import time

f = open("aaaa.txt") for line in f:
    line = line.strip() # print line  if len(line) > 6: pass   elif not (re.match("\d", line)): pass  elif len(line) < 6:
        a = len(line)
        b = 6  c = b - a
        d = '0' * c
        e = d + line print e else: print line

zhao