Counting a's (3) X55221
Write a function count_a(s, stop) that given a string s and a character stop returns the number of times that letter a occurs in s before the first appearance of character stop. If character stop is not in s, the function must return −1.
Sample session
>>> count_a('naturally', 'u') 1 >>> count_a('russian', 't') -1 >>> count_a('adaptation', 'a') 0 >>> count_a('adaptation', 'n') 3
Information
- Author
- ProAl
- Language
- English
- Official solutions
- Python
- User solutions
- Python