python os.rename模块删除文件

Question

I've wrote a little program to rename a big bunch of files in python

#!/usr/local/bin/python3

import os
import glob
import sys

script, arg1 = sys.argv
f = open(arg1)

# Create a filelist using glob
filelist = glob.glob('*.avi')
filelist.sort()

for filename in filelist:
    print(filename)
    # To keep the file ending
    os.rename(filename, f.readline()[:-1]+filename[-4:])

It reads the names out of a txt-file which is given as an argument and renames the other avi files. But there was one file missing with the start number '102' so now the complete order from '102' on is wrong. If I now rerun this file and delete the line 102 in my txt file every file from 102 on is deleted except the last one.
May you know how to fix this little bug and can explain to me how this happens because I work on this far too long.

---Edit---

A short snippet of my text file

snip
099. Abenteuer in Ido 
100. Corsa, der junge Rebell 
101. Unser Papa ist ein Held 
102. Die Gesetze des Vertrauens 
103. Um acht in Spider's Cafe 
104. Ruffy gegen Vivi 
105. Aufruhr in Rainbase 
snip

The list goes on up to 400. I've got 300 files so the problem with os.rename won't happen. The file with the number 102 didn't exist when i first ran the script, so everything above is one number wrong. I added the file 102 and want to rerun this script.

The files before I rerun:

...
100. Corsa, der junge Rebell.avi 
101. Unser Papa ist ein Held.avi 
102. Die Gesetze des Vertrauens.avi 
103. Um acht in Spider's Cafe.avi 
104. Ruffy gegen Vivi.avi 
105. Aufruhr in Rainbase.avi
... 

The files afterwards:

...
100. Corsa, der junge Rebell.avi 
101. Unser Papa ist ein Held.avi 
301. Sogeking, der Held der Stunde.avi
... 

If you need any more information I will provide it as well as possible

Answer 1

Ok. I figured the problem out thanks to Corley. When i rerun the program with the one entry of the missing file deleted I get double names which will delete the files as Corley described. I fixed this with a loop which renames all my files to simple number

i = 1
for filename in filelist:
    os.rename(filename, str(i).zfill(4)+'temp'+filename[-4:])
    i+=1

• 001.temp.avi
• 002.temp.avi
• 003.temp.avi
• ...

and so on. Then i rename the files like they should be with the script in my initial question.

Thanks for helping me figure it out.

Answer 2

You probably have fewer lines in your file than you have files in the directory. I'm guessing this is a unix environment?

readline has this side effect, from the docs:

f.readline() reads a single line from the file; a newline character (\\n) is left at the end of the string, and is only omitted on the last line of the file if the file doesn't end in a newline. This makes the return value unambiguous; if f.readline() returns an empty string, the end of the file has been reached, while a blank line is represented by '\\n', a string containing only a single newline.

os.rename has this side effect, from the docs:

On Unix, if dst exists and is a file, it will be replaced silently if the user has permission.

You can probably guess what's going wrong by now, but i'll spell it out just in case:

Let's say you have 5 files in your directory:

• a.txt
• b.txt
• c.txt
• d.txt
• e.txt

And in your input file, you only have 3 entries:

User1
User2
User3

The expectation is that you want a.txt renamed to User1.txt , etc. Though, it's all implicit of course.

So, your script will rename a.txt to User1.txt , then b.txt to User2.txt , then c.txt to User3.txt .

What happens for d.txt ? It will read the file, and get an empty string. It will then add the original extension onto the file, and rename d.txt to .txt . Not very useful.

It gets worse... now, we look at e.txt . It will read the file again with readline() and get another empty string. It will then again add the original extension onto the file, and rename e.txt to .txt . Since there's already a file with that name, it gets deleted and now d.txt just disappears altogether.

Answer 3

This is the script I use to batch rename my files, ensuring that no files are deleted when I run it. It first renames any .wav file in a folder to another folder I created called "temp" with a UUID. Then, it renames the files back to the target folder and names them whatever the folder name is plus a sequential number starting at 0.

#!/usr/bin/env python
import os, uuid

path = "/Users/user/Target Folder/A/"
temp = "/Users/user/temp/"
ext = ".wav"

# Get directory name
for path, sub_directories, files in os.walk(path):
    directory_name = os.path.basename(os.path.dirname(path))

# Rename with UUID to temp folder
for i,filename in enumerate(os.listdir(path)):
    if filename.endswith(ext):
       os.rename(path+filename, temp+str(uuid.uuid4())+ext)

# Rename the files to Folder name plus number
for i,filename in enumerate(os.listdir(temp)):
    if filename.endswith(ext):
        os.rename(temp+filename, path+directory_name+str(i).zfill(0)+ext)