小白自学Python，仅做个人消息记录。

Exercise 1: Write a while loop that starts at the last character in thestring and works its way backwards to the first character in the string,printing each letter on a separate line, except backwards.

from operator import index


your_string = 'adsfgaeqgasdhergherhre'

index = -1

while index >= -(len(your_string)):
    letter = your_string[index]
    print(letter)
    index = index - 1

Exercise 3: Encapsulate this code in a function named count, andgeneralize it so that it accepts the string and the letter as arguments.

def CountString(your_string, letter):
    count = 0
    for letter_you_need in your_string:
        if letter_you_need == letter:
            count += 1
    print(count) 

CountString('AppDataaaa2022pythonexe', 'e')