python - 为什么这会打印两次错误消息？

Question

stackoverflow 新手，以及 python (python-3) 新手。目前在 edx.org 上学习并遇到以下错误。

我创建了一个函数，用于根据答案 str 检查用户输入的 str 并返回 True 或 False>.

在测试该函数时，我创建了一个 while 循环以在第三次不成功的尝试时停止。但是，每当尝试不成功时，该函数就会将错误消息打印两次，而实际上它应该只打印一次。

我通过将函数返回的 Bool 值存储到变量中来修复错误，而不是直接在 while< 内的 if 条件中调用该函数/strong> 循环。但是，我想了解错误消息打印两次背后的逻辑。这是打印错误消息两次的原始代码:

def letter_guess(letter, guess):

    if len(guess) == 1 and guess.isalpha() and guess < letter:
        print(guess,"is lower than the answer. Try again.\n")
        return False

    elif len(guess) == 1 and guess.isalpha() and guess > letter:
        print(guess,"is higher than the answer. Try again.\n")
        return False

    elif len(guess) == 1 and guess.isalpha() and guess == letter:
        print("Correct answer!")
        return True

    else:
        print("Please only enter one alphabet for the letter. Try again.\n")
        return False

answer2 = "m"
guess2 = input("Please enter a single alphabet : ")    

i = 0

while i < 3:


    if letter_guess(answer2, guess2):
        break

    elif letter_guess(answer2, guess2) == False and i == 2:
        print("You have reached 3 guesses. Game over.")
        break

    else:
        i += 1
        guess2 = input("Please guess again : ")

Answer 1

您想在 while 循环内调用 input():

# ...
answer2 = "m"
i = 0
while i < 3:
    guess2 = input("Please enter a single alphabet : ")
    # ...

否则用户没有机会更改他们的答案，guess2 永远不会更改，并且他们会多次收到相同的错误消息。