Just know a new module in Python standard library called glob. This module helps you get files in your desired pattern. * matches any characters, ?matches single character, [] matches a character in square brackets range.
For example, if you have files
12abc.pdf
ut.bmp
051.txt
uc.pdf
Here is some examples of glob.glob(pathname):
import glob
glob.glob("*.*")['051.txt', '12abc.pdf', 'uc.pdf', 'ut.bmp']
glob.glob("[0-9]*.*")['051.txt', '12abc.pdf']
glob.glob("[0-9]*.pdf")['12abc.pdf']
glob.glob("[0-9].pdf")[]
glob.glob("?.*")
glob.glob("?.pdf")
glob.glob("??.pdf")
[]
[]
['uc.pdf']
There is another function glob.iglob(pathname) which return yields the same values as glob() as an iterator.
The official documents can be find here