Renaming a directory of pdf files using Python almost works

Question

I have been trying to add "Q3" to the beginning of 89 pdf files within one folder. I have managed to get results with the solution presented HERE

this works but only for roughly 10-15 files before it stops with a variety of errors it seems and without a defined order meaning the roughly 10-15 is different each time. i either receive a "FileNotFoundError: [WinError 2] The system cannot find the file specified:" or "PermissionError: [WinError 32] The process cannot access the file because it is being used by another process:"

I understand the "permissionserror" is because the .py file I am working on and running is located in the same directory as the pdf files so it is running over this file. But putting it within the same directory was suggested in the above linked solution to solve the WinError2 and prior to doing so it would not do anything.

*first part of code is to delete some unwanted files that show up and may not be relevant to question

import os
my_dir = "DIRECTORY OF PDF FILES"
for fname in os.listdir(my_dir):
    if fname.startswith('Copy') or fname.startswith('SxDI'):
        os.remove(os.path.join(my_dir, fname))

for fname in os.listdir(my_dir):
    os.rename(fname, "Q3" + fname)

My apologies did not copy fully. link is working – Ungara Jan 17 '17 at 23:19 — Ungara, Jan 17 '17 at 23:19

score 0 · Answer 1 · answered Jan 17 '17 at 23:14

It looks like you are changing the list that you are iterating over.

Try:

files_to_rename = [fname in os.listdir(my_dir) if not (fname.startswith('Copy') or fname.startswith('SxDI'))]

for fname in files_to_rename:
    os.rename(fname, "Q3" + fname")

This is untested, but the idea is to grab the name of everything you need to change first, then go change them.

Renaming a directory of pdf files using Python almost works

1 Answers1