The python exercise program changes the file name in batches

# encoding:utf-8
##
#  The file name as :
#  Next! .mp3
##
import os,re
fs=os.listdir('xb')
for f in fs:
 ###### Method one: partition Get the null character 
 #1. Change the file name to '[' Operators are divided into 3 Part of the 
 #ls=f.partition('[')
 #2.ls[0] Is required for the file name, so get ls[1:]
 #dirtystring = ''.join(ls[1:])
 #3. Began to replace 
 #newname=f.replace(dirtystring, '') + '.mp3')
 #os.rename('xb/' + f, newname)
 ###### Method 2: get useless characters regularly 
 dirtymatch = re.search(r'[.*?]', f)
 if dirtymatch:
  dirtystring=dirtymatch.group(0)
  newname=f.replace(dirtystring, '') + '.mp3'
  os.rename('xb/' + f, newname)
 # Note: can be used directly re.sub Method to replace the filename with no characters