exercise 8.6 - find

"""=========================

exercise 8.6

========================="""

def find(word, letter, start):

    index = start

    while index < len(word):

        if word[index] == letter:

            return index

        index = index + 1

    return -1

def count_v2 (word, letter, start):

    

    how_many = 0

    index = find(word, letter, start)

    

    if index == -1:

        how_many = 0

    else:

        while index > -1:

            how_many = how_many + 1

            index = index+1

            index = find(word, letter, index)

    print how_many

    

count_v2 ('banana', 'x', 0)    

count_v2 ('banana', 'a', 4)

count_v2 ('banana', 'a', 2)

count_v2 ('banana', 'a', 0)