Use wildcard with os.path.isfile()

Question

I'd like to check if there are any .rar files in a directory. It doesn’t need to be recursive.

Using wildcard with os.path.isfile() was my best guess, but it doesn't work. What can I do then?

Solution 1

glob is what you need.

>>> import glob
>>> glob.glob('*.rar')   # all rar files within the directory, in this case the current working one

os.path.isfile() returns True if a path is an existing regular file. So that is used for checking whether a file already exists and doesn't support wildcards. glob does.

Solution 2

Without using os.path.isfile() you won't know whether the results returned by glob() are files or subdirectories, so try something like this instead:

import fnmatch
import os

def find_files(base, pattern):
    '''Return list of files matching pattern in base folder.'''
    return [n for n in fnmatch.filter(os.listdir(base), pattern) if
        os.path.isfile(os.path.join(base, n))]

rar_files = find_files('somedir', '*.rar')

You could also just filter the results returned by glob() if you like, and that has the advantage of doing a few extra things relating to unicode and the like. Check the source in glob.py if it matters.

[n for n in glob(pattern) if os.path.isfile(n)]

Solution 3

import os
[x for x in os.listdir("your_directory") if len(x) >= 4 and  x[-4:] == ".rar"]

Solution 4

Wildcards are expanded by shell and hence you can not use it with os.path.isfile()

If you want to use wildcards, you could use popen with shell = True or os.system()

>>> import os
>>> os.system('ls')
aliases.sh          
default_bashprofile     networkhelpers          projecthelper.old           pythonhelpers           virtualenvwrapper_bashrc
0
>>> os.system('ls *.old')
projecthelper.old
0

You could get the same effect with glob module too.

>>> import glob
>>> glob.glob('*.old')
['projecthelper.old']
>>> 

Solution 5

If you just care about whether at least one file exists and you don't want a list of the files:

import glob
import os

def check_for_files(filepath):
    for filepath_object in glob.glob(filepath):
        if os.path.isfile(filepath_object):
            return True

    return False

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