find words (with one or more of a selection of characters) in a source file and save them to a new file

find_words_with_regex.py

# -*- coding: utf-8 -*-
import re 
from random import shuffle

look_for = 'áàãâéêçíóôõúü'
omit = '[,:;.()!"?]'
max_amount = 2000000

pattern = r'[^\s]*'+ '[' + re.escape(look_for) + ']' + r'[^\s]*'
found_words = []

with open('source-text.txt', encoding='utf-8') as f:
    for l in f.readlines():
        l = re.sub(omit, ' ', l)
        matches = re.findall(pattern, l, flags=0)
        found_words.extend(matches)

with open('filtered_words.txt', 'w', encoding='utf-8') as target:
    result = list(set(found_words))
    shuffle(result)
    if len(result) < max_amount: 
    	max_amount = len(result)
    target.write('\n'.join(result[:max_amount]))