<s>[INST] How to list all files of a directory in Python How can I list all files of a directory in python and add them to a list?
 [/INST] os.listdir() will get you everything that's in a directory - files and directories.
If you want just files, you could either filter this down using os.path:
from os import listdir
from os.path import isfile, join
onlyfiles = [f for f in listdir(mypath) if isfile(join(mypath, f))]

or you could use os.walk() which will yield two lists for each directory it visits - splitting into files and dirs for you. If you only want the top directory you can just break the first time it yields
from os import walk

f = []
for (dirpath, dirnames, filenames) in walk(mypath):
    f.extend(filenames)
    break

And lastly, as that example shows, adding one list to another you can either use .extend() or 
>>> q = [1, 2, 3]
>>> w = [4, 5, 6]
>>> q = q + w
>>> q
[1, 2, 3, 4, 5, 6]

Personally, I prefer .extend()
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