Python sort files by filename with numbers as first letters

Question

I have the following list which is the output of mylist.sort()

['0_sound.wav', '10_sound.wav', '15_sound.wav', '20_sound.wav', '5_sound.wav']

This makes sense, since the filenames are treated as strings. But I want the following order:

['0_sound.wav', '5_sound.wav', '10_sound.wav', '15_sound.wav', '20_sound.wav']

What is a good way of archieving this? The filename may vary, it´s not always "sound", which would make it easier.

Will there always be this `_` as a separator between the number and the word? — Ofer Sadan, Aug 21 '22 at 12:39

score 4 · Accepted Answer · answered Aug 21 '22 at 12:41

Assuming that there will always be an underscore _ as a separator:

files = ['0_sound.wav', '10_sound.wav', '15_sound.wav', '20_sound.wav', '5_sound.wav']
files.sort(key=lambda x: int(x.split('_')[0]))

Result:

['0_sound.wav', '5_sound.wav', '10_sound.wav', '15_sound.wav', '20_sound.wav']

Note: This will fail if there are unexpected filenames that don't have this separator or that don't start with a number, if that is even possible I would suggest filtering that list first so you don't get unexpected errors

thank you, that lambda function as key is pretty cool – Data Mastery Aug 21 '22 at 13:02 — Data Mastery, Aug 21 '22 at 13:02

Python sort files by filename with numbers as first letters

1 Answers1