批量更改文件后缀

import os, stringdef myrename(path,old_ext,new_ext):    if path[-1]!="\\":        path=path+"\\"        ff = os.listdir(path)    fname = [x for x in ff if os.path.isfile(path+x)]    for file in fname:        f = os.path.splitext(file)        if f[1] == old_ext:            fnewname = f[0]+new_ext            os.rename(path+file,path+fnewname)      myrename(r"C:\Users\",".mp4",".mp3")

os.rename的使用中，文件名需要包含路径信息。