Python - Loop through list within regex

Question

Right, i'm relatively new to Python, which you will likely see in my code, but is there any way to iterate through a list within regex?

Basically, i'm looping through each filename within a folder, getting a code (2-6 digits) from the filename, and i'm wanting to compare it with a list of codes in a text file, which have a name attached, in the format "1234_Name" (without the quotation marks). If the code exists in both lists, I want to print out the list entry, i.e. 1234_Name. Currently my code only seems to look at the first entry in the text file's list and i'm not sure how to make it look through them all to find matches.

import os, re

sitesfile = open('C:/Users/me/My Documents/WORK_PYTHON/Renaming/testnames.txt', 'r')
filefolder = r'C:/Users/me/My Documents/WORK_PYTHON/Renaming/files/'

sites = sitesfile.read()
site_split = re.split('\n', sites)


old = []
newname = []

for site in site_split:
    newname.append(site)


for root, dirs, filenames in os.walk(filefolder):
    for filename in filenames:
        fullpath = os.path.join(root, filename)
        filename_split = os.path.splitext(fullpath) 
        filename_zero, fileext = filename_split
        filename_zs = re.split("/", filename_zero)
        filenm = re.search(r"[\w]+", str(filename_zs[-1:]))#get only filename, not path
        filenmgrp = filenm.group()

        pacode = re.search('\d\d+', filenmgrp)
        if pacode:
            pacodegrp = pacode.group()
            match = re.match(pacodegrp, site)
            if match:
                 print site

Hope this makes sense - thanks a lot in advance!

Answer 1

So, use this code instead:

import os
import re
def locate(pattern = r'\d+[_]', root=os.curdir):
    for path, dirs, files in os.walk(os.path.abspath(root)):
        for filename in re.findall(pattern, ' '.join(files)):
            yield os.path.join(path, filename)

..this will only return files in a folder that match a given regex pattern.

with open('list_file.txt', 'r') as f:
     lines = [x.split('_')[0] for x in f.readlines()]

print_out = []

for f in locate(<your code regex>, <your directory>):
    if f in lines: print_out.append(f)

print(print_out)

...find the valid codes in your list_file first, then compare the files that come back with your given regex.