如何使用re.sub实际替换文件名？

Question

I put together a regular expression that works using the mac program Patterns , when I use the code in my python script, I cannot get the changes made to the filenames. I know that you need to assign the output of re.sub to a new string, which is a common error. I did that, but I still cannot get the correct results.

Here is my code with the given file names as input:

real.time.With.bill.maher.JUST.OVERTIME.2014.01.31.WEB-DL.Shadoe

real time with bill maher 2014 01 24 hdtv x264-2hd.mp4

Real Time With Bill Maher 2014.02.07.hdtv.x264-2hd.mp4

import re
import os

path = "/Users/USERNAME/Movies"
pattern = "(real[. ]time[. ]with[. ]bill[. ]maher[. ])"
replacement = "Real Time with Bill Maher "

def renamer(path, pattern, replacement):
    for dirpath,_,file in os.walk(path):
        for oldname in file:
            if re.search(pattern, oldname, re.I):
                newname = re.sub(pattern, replacement, oldname)
                newpath = os.path.join(dirpath, newname)
                oldpath = dirpath + "/" + oldname
                print newpath + " < new"
                print oldpath
                os.rename(oldpath, newpath)

renamer(path, pattern, replacement)

Answer 1

The code is missing re.I flag in re.sub call:

>>> pattern = "(real[. ]time[. ]with[. ]bill[. ]maher[. ])"
>>> replacement = "Real Time with Bill Maher "
>>> re.sub(pattern, replacement, 'real.time.With.bill.maher.JUST.OVERTIME.2014.01.31.WEB-DL.Shadoe')
'real.time.With.bill.maher.JUST.OVERTIME.2014.01.31.WEB-DL.Shadoe'
>>> re.sub(pattern, replacement, 'real.time.With.bill.maher.JUST.OVERTIME.2014.01.31.WEB-DL.Shadoe', flags=re.I)
'Real Time with Bill Maher JUST.OVERTIME.2014.01.31.WEB-DL.Shadoe'

You should specify flags as keyword argument, otherwise it is recognized as count (replace count) argument.