ex_09_5.py

#!/usr/bin/python
#AUTHOR: alexxa
#DATE: 27.12.2013
#SOURCE: Think Python: How to Think Like a Computer Scientist by Allen B. Downey
# http://www.greenteapress.com/thinkpython/html/index.html
#PURPOSE: Chapter 9. Case study: word play

# Exercise 9.5

# Write a function named uses_all that takes a word and 
# a string of required letters, and that returns True if 
# the word uses all the required letters at least once. 
# How many words are there that use all the vowels aeiou? 
# How about aeiouy?

def uses_all(word, string):
    for letter in string:
        if letter not in word:
            return False
    return True


def vowels(string):
    fin = open('words.txt')
    count = 0
    for line in fin:
        word = line.strip()
        if uses_all(word, string):
            count +=1
    print('There are {} words which contain all "{}" letters at once.'.format(count,string))
        
vowels('aeiou')
vowels('aeiouy')

#END