import os
import re
def filename_modify(target,expandname,position = "end",oldstr = "",newstr = ""):
    #判断路径是否存在
    if os.path.exists(target) == False:
        raise Exception("path is not exist!")
    #遍历文件夹中的名字
    for file in os.listdir(target):

        filename = os.path.splitext(file)[0]
        fileexpand = os.path.splitext(file)[1]

        # 避开文件夹
        # if os.path.isdir(os.path.join(target,file)):
        #     continue
        #避开文件夹 第二种方法
        if fileexpand == "":
            continue
        #判断修改位置
        if position == "head":
            newname = expandname+filename+fileexpand
        elif position == "end":
            newname = filename+expandname+fileexpand
        elif position == "replace":
            pattern = re.findall(oldstr,filename)
            for value in pattern:
                filename = filename.replace(value,newstr)
            newname = filename+fileexpand
        oldpath = os.path.join(target,file)
        newpath = os.path.join(target,newname)
        os.rename(oldpath,newpath)


filename_modify("文件夹的位置","要增加的名称","修改位置","需要替换的就名称","需要替换的新名称")