Exclude list of letters in a string from list of words

Question

I am a bit in trouble in a way to select a bunch of letters in a for loop that select words in a list which do not contain these letters;

Bellow the code I am trying to use, when I assign string with just one char, it print all words in words.txt that do not contain that char, but if I assign string with more than one char it consider the whole string, even using a ( for letter in string )

def avoids_2():
    string = 'abc'
    fin = open('words.txt')
    for letter in string: 
        for line in fin:
            if letter not in line:
                word = line.strip()
                print(word) 

Please, does anyone knows how to solve?

Answer 1

Issue with your code is that you are searching for only one character at a time ie if your letter is c it will look for only c and print strings with a or b too in the internal loop. So you can change it like this

fin = open('words.txt')
test_string = 'abc'
for line in fin:
    flag = False
    for letter in test_string:
        if letter in line:
            flag = True
            break
    if not flag:
        print(line.strip())

You can also use regex here

import re

fin = open('words.txt')

for line in fin:
   if re.match(r'a|b|c', line):
      continue
   print(line.strip())