#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# string and word list definitions
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

def scrub(word):
    return word.strip().lower()

def load_word_list(filename='dictionary.txt'):
    word_file = open(filename, 'r')
    word_list = []
    for word in word_file:
        word_list.append( scrub(word) )
    return word_list

def count_words(word_list):
    list_of_counts = [0] * 26
    for word in word_list:
        index = position_for(word[0])
        list_of_counts[index] += 1
    return list_of_counts

def position_for(ch):
    index = ord(ch) - ord('a')
    # index = 'abcdefghijklmnopqrstuvwxyz'.find(letter)
    return index

words  = load_word_list()
counts = count_words(words)

print('The list "counts" contains the number of words by first letter:')
print(counts, end='\n\n')

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# solution to the exercise
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

def look_up(letter, count_list):
    index = ord(letter) - ord('a')
    # index = 'abcdefghijklmnopqrstuvwxyz'.find(letter)
    return count_list[index]

while True:
    letter = input('Enter a letter: ')
    letter = letter.lower()
    if len(letter) == 1 and letter.isalpha():
        break

total_words = sum(counts)
words_for_letter = look_up(letter, counts)
percent_for_letter = (words_for_letter/total_words) * 100

print()
print(words_for_letter, 'of the words start with', letter + '.')
print('That is {:5.2f}% of all words.'.format(percent_for_letter))
print()