python更改文件夹下文件名字

'''
Created on 2013-1-2

@author: buptlishantao
'''

#!/usr/bin/python

import re
import os
import time

def change_name(path):
    global i
    if not os.path.isdir(path) and not os.path.isfile(path):
    
        return False
    if os.path.isfile(path):
    
        file_path = os.path.split(path) #split the path  into path name   and file name
        
        lists = file_path[1].split('.')
        file_ext = lists[-1] 
        img_ext = ['bmp','jpeg','gif','psd','png','JPG','jpg']
        if file_ext in img_ext:
        
            os.rename(path,file_path[0]+'/'+lists[0]+'_fc.'+file_ext)
            i+=1 
        
    elif os.path.isdir(path):
        for x in os.listdir(path):
        
            change_name(os.path.join(path,x)) 
img_dir = os.getcwd()
start = time.time()
i = 0
print img_dir
change_name(img_dir)
c = time.time()-start
print('time:%0.2f'%(c))
print('number %s '%(i))