regular expression usage in glob.glob for python

Question

import glob

list = glob.glob(r\'*abc*.txt\') + glob.glob(r\'*123*.txt\') + glob.glob(r\'*a1b*.txt\')

for i in list:
  print i

This code works to

Answer 1

for filename in glob.iglob(path_to_directory + "*.txt"):
    if filename.find("abc") != -1 or filename.find("123") != -1 or filename.find("a1b") != -1:
        print filename