Python批量修改文件夹里文件的名称

import sys, string, os, shutil
#输入目录名和前缀名，重命名后的名称结构类似prefix_0001
def RenameFiles(srcdir, prefix):
srcfiles = os.listdir(srcdir)
index = 1
for srcfile in srcfiles:
srcfilename = os.path.splitext(srcfile)[0][1:]
sufix = os.path.splitext(srcfile)[1]
#根据目录下具体的文件数修改%号后的值，"%04d"最多支持9999
destfile = srcdir + "//" + prefix + "_%04d"%(index) + sufix
srcfile = os.path.join(srcdir, srcfile)
os.rename(srcfile, destfile)
index += 1
print destfile
srcdir = "D://Music"
prefix = "IMG_2011"
RenameFiles(srcdir, prefix)