python iterate through files in directory

import os
directory = 'the/directory/you/want/to/use'

for filename in os.listdir(directory):
    if filename.endswith(".txt"):
      #do smth
      continue
    else:
    continue

import os

for filename in os.listdir(directory):
    if filename.endswith(".asm") or filename.endswith(".py"): 
         # print(os.path.join(directory, filename))
        continue
    else:
        continue

import os

for filename in os.listdir(directory):
    if filename.endswith(".asm") or filename.endswith(".py"): 
         # print(os.path.join(directory, filename))
        continue
    else:
        continue

import glob

globIterator = glob.iglob(path, recursive=True)

run = True
while(run == True):
    try:
        print(next(globIterator))
    except:
        run = False