dictionary = {} words = input("Introduce la lista de palabras y traducciones en formato palabra:traducción separadas por comas: ") for i in words.split(','): key, value = i.split(':') dictionary[key] = value phrase = input('Introduce una frase en español: ') for i in phrase.split(): if i in dictionary: print(dictionary[i], end=' ') else: print(i, end=' ')

You can use the following code to get the desired output.
import re
import sys

def main():
    with open(sys.argv[1]) as f:
        for line in f:
            if re.search(r'(^|\s)@(\w+)', line):
                print(line.strip())

if __name__ == '__main__':
    main()

The output will be