Python function that similar to bash find command

Question

I have a dir structure like the following:

[me@mypc]$ tree .
.
├── set01
│   ├── 01
│   │   ├── p1-001a.png
│   │   ├── p1-001b.png
│   │   ├── p1-001c.png
│   │   ├── p1-001d.png
│   │   └── p1-001e.png
│   ├── 02
│   │   ├── p2-001a.png
│   │   ├── p2-001b.png
│   │   ├── p2-001c.png
│   │   ├── p2-001d.png
│   │   └── p2-001e.png

I would like to write a python script to rename all *a.png to 01.png, *b.png to 02.png, and so on. Frist I guess I have to use something similar to find . -name '*.png', and the most similar thing I found in python was os.walk. However, in os.walk I have to check every file, if it's png, then I'll concatenate it with it's root, somehow not that elegant. I was wondering if there is a better way to do this? Thanks in advance.

Answer 1

For a search pattern like that, you can probably get away with glob.

from glob import glob
paths = glob('set01/*/*.png')

Answer 2

You can use os.walk to traverse the directory tree. Maybe this works?

import os

for dpath, dnames, fnames in os.walk("."):
  for i, fname in enumerate([os.path.join(dpath, fname) for fname in fnames]):
    if fname.endswith(".png"):
      #os.rename(fname, os.path.join(dpath, "%04d.png" % i))
      print "mv %s %s" % (fname, os.path.join(dpath, "%04d.png" % i))

For Python 3.4+ you may want to use pathlib.glob() with a recursive pattern (e.g., **/*.png) instead:

• Recursively iterate through all subdirectories using pathlib
• https://docs.python.org/3/library/pathlib.html#pathlib.Path.glob
• https://docs.python.org/3/library/pathlib.html#pathlib.Path.rglob