用 python 替换文件名字符

我有一些代码将单词“_manual”添加到一堆文件名的末尾。 我需要更改脚本，以便删除文件名的最后两个字母 (ES)，然后将其替换为 _ES_Manual 例如：AC-5400ES.txt --> AC-5400_ES_manual.txt

我如何将该函数合并到这段代码中？

folder = r"C:/Documents and Settings/DuffA/Bureaublad/test"
import os # glob is unnecessary
for root, dirs, filenames in os.walk(folder):
    for filename in filenames:
        fullpath = os.path.join(root, filename)
        filename_split = os.path.splitext(fullpath) # filename and extensionname (extension in [1])
        filename_zero, fileext = filename_split
        print fullpath, filename_zero + "_manual" + fileext
        os.rename(fullpath, filename_zero + "_manual" + fileext)

尝试这个：

import os
pathiter = (os.path.join(root, filename)
    for root, _, filenames in os.walk(folder)
    for filename in filenames
)
for path in pathiter:
    newname =  path.replace('ES.txt', '_ES_manual.txt')
    if newname != path:
        os.rename(path,newname)