Question

I’m designing a program that looks through a list of words, and counts how many words only have the letters p, y, t, h, o and n in them.

So far, my code is:

def find_python(string, python):
 """searches for the letters 'python' in the word."""
 for eachLetter in python:
    if eachLetter not in string:
        return False
 return True

def main():
 python = 'python'
 how_many = 0

 try:
 fin = open('words.txt')#open the file
 except:
     print("No, no, file no here") #if file is not found
 for eachLine in fin:
    string = eachLine
    find_python(string, python)
if find_python(string, python) == True:
    how_many = how_many + 1#increment count if word found
 print how_many#print out count
 fin.close()#close the file

if __name__ == '__main__':
main()

However, my code is returning the incorrect number of words, for example, it will return the word ‘xylophonist’ if I put in the print statement for it because it has the letters python in it. What should I do so it will reject any word that has forbidden letters?

Answer 1

Correct your test function:

def find_python(string, python):
 """searches for the letters 'python' in the word.
    return True, if string contains only letters from python.
 """
 for eachLetter in string:
    if eachLetter not in python:
        return False
 return True