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
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