Looking For File Traversal Functions In Python That Are Like Java's

In Java you can do File.listFiles() and receive all of the files in a directory. You can then easily recurse through directory trees. Is there an analogous way to do this in Pytho

Solution 1:

Yes, there is. The Python way is even better.

There are three possibilities:

1) Like File.listFiles():

Python has the function os.listdir(path). It works like the Java method.

2) pathname pattern expansion with glob:

The module glob contains functions to list files on the file system using Unix shell like pattern, e.g.

files = glob.glob('/usr/joe/*.gif')

3) File Traversal with walk:

Really nice is the os.walk function of Python.

The walk method returns a generation function that recursively list all directories and files below a given starting path.

An Example:

import os
from os.path import join
for root, dirs, files inos.walk('/usr'):
   print"Current directory", root
   print"Sub directories", dirs
   print"Files", files

You can even on the fly remove directories from "dirs" to avoid walking to that dir: if "joe" in dirs: dirs.remove("joe") to avoid walking into directories called "joe".

listdir and walk are documented here. glob is documented here.

Solution 2:

As a long-time Pythonista, I have to say the path/file manipulation functions in the std library are sub-par: they are not object-oriented and they reflect an obsolete, lets-wrap-OS-system-functions-without-thinking philosophy. I'd heartily recommend the 'path' module as a wrapper (around os, os.path, glob and tempfile if you must know): much nicer and OOPy: http://pypi.python.org/pypi/path.py/2.2

This is walk() with the path module:

dir = path(os.environ['HOME'])
for f in dir.walk():
    if f.isfile() and f.endswith('~'):
        f.remove()

Solution 3:

Try "listdir()" in the os module (docs):

import osprintos.listdir('.')

Solution 4:

Straight from Python's Refererence Library

>>> import glob
>>> glob.glob('./[0-9].*')
['./1.gif', './2.txt']
>>> glob.glob('*.gif')
['1.gif', 'card.gif']
>>> glob.glob('?.gif')
['1.gif']

Solution 5:

Take a look at os.walk() and the examples here. With os.walk() you can easily process a whole directory tree.

An example from the link above...

# Delete everything reachable from the directory named in'top',
# assuming there are no symbolic links.
# CAUTION:  This is dangerous!  For example, if top == '/', it
# could delete all your disk files.
import osfor root, dirs, files inos.walk(top, topdown=False):
    for name in files:
        os.remove(os.path.join(root, name))
    for name in dirs:
        os.rmdir(os.path.join(root, name))