View source for Finding files in a directory: glob


== Goal ==
We want to deal with many files in a directory. What is an easy way to get the filename in a directory?

Questions to [mailto:davrot@uni-bremen.de David Rotermund]

== Creating test files ==
<syntaxhighlight lang="python">from pathlib import Path

Path("Testfile_1.mat").touch()
Path("Testfile_2.mat").touch()
Path("Testfile_10.mat").touch()
Path("Testfile_3.mat").touch()</syntaxhighlight>

== Using glob in a for-loop ==
<syntaxhighlight lang="python">import glob

for filename in glob.glob("*.mat"):
    print(filename)</syntaxhighlight><syntaxhighlight lang="python">Testfile_1.mat
Testfile_2.mat
Testfile_10.mat
Testfile_3.mat</syntaxhighlight>

== Using glob to create a list ==
<syntaxhighlight lang="python">import glob

list = glob.glob("*.mat")
print(list)</syntaxhighlight><syntaxhighlight lang="python">['Testfile_1.mat', 'Testfile_2.mat', 'Testfile_10.mat', 'Testfile_3.mat']</syntaxhighlight>

=== Sorting the filenames ===
<syntaxhighlight lang="python">import glob

list = sorted(glob.glob("*.mat"))
print(list)</syntaxhighlight><syntaxhighlight lang="python">['Testfile_1.mat', 'Testfile_10.mat', 'Testfile_2.mat', 'Testfile_3.mat']</syntaxhighlight>Hmmm… This result is not helpful.

=== Sorting the filenames with [https://pypi.org/project/natsort/ natsort] ===
<syntaxhighlight lang="shell">pip install natsort</syntaxhighlight><syntaxhighlight lang="python">import glob
from natsort import natsorted

list = natsorted(glob.glob("*.mat"))
print(list)</syntaxhighlight><syntaxhighlight lang="python">['Testfile_1.mat', 'Testfile_2.mat', 'Testfile_3.mat', 'Testfile_10.mat']</syntaxhighlight>

== rsplit ==
And maybe you don’t want to have the file extensions. Then we can use [https://docs.python.org/3/library/stdtypes.html#str.rsplit rsplit] on the string.<syntaxhighlight lang="python">import glob
from natsort import natsorted

for filename in natsorted(glob.glob("*.mat")):
    print(filename.rsplit(".", 1)[0])</syntaxhighlight><syntaxhighlight lang="python">Testfile_1
Testfile_2
Testfile_3
Testfile_10</syntaxhighlight>Alternatively without a for-loop but using [https://docs.python.org/3/library/functions.html#map map] , [https://docs.python.org/3/library/functions.html#func-list list] and [https://docs.python.org/3/reference/expressions.html#lambda lambda functions]:<syntaxhighlight lang="python">import glob
from natsort import natsorted

filenames = natsorted(glob.glob("*.mat"))
filenames = list(map(lambda s: s.rsplit(".", 1)[0], filenames))
print(filenames)</syntaxhighlight><syntaxhighlight lang="python">['Testfile_1', 'Testfile_2', 'Testfile_3', 'Testfile_10']</syntaxhighlight>