Python猜数字游戏猜对仍显示失败提示 如何让代码仅在for循环结束后执行

问题原因 #

末尾的失败提示打印语句没有附加任何判断条件，无论for循环是因为猜对数字执行break提前退出，还是猜测次数耗尽自然结束，这行代码都会被执行，因此出现猜对后依然弹出失败提示的问题。仅调整缩进只能控制这行代码是否属于循环体，无法解决逻辑判断缺失的问题。

修复方案 #

方案1：使用Python for循环自带的else分支 #

Python的for...else是原生支持的语法，仅当for循环完整跑完所有迭代、没有被break中断时，才会执行else块下的代码，完全匹配你的需求，修改后代码如下：

def main(random_pick, guesses):
    for i in range(guesses):
        try:
            guess = int(input(f"{BLUE}[ ? ]{WHITE} Guess the number : "))
            if guess > random_pick:
                print(f"{RED}[ ! ]{WHITE} Your guess is high!")
            elif guess < random_pick:
                print(f"{RED}[ ! ]{WHITE} Your guess is low")
            else:
                print(f"{GREEN}[ $ ]{WHITE} You guessed it! Congratulations")
                break
        except ValueError:
            print(f"{RED}[ ! ]{WHITE} Wrong value, try again!")
    else:
        print(f"{YELLOW}[ ! ]{WHITE} Better luck next time, the number was {random_pick}")

方案2：新增状态变量判断游戏结果 #

如果不习惯for...else的写法，也可以新增布尔变量标记是否猜对，最后根据变量值判断是否输出失败提示：

def main(random_pick, guesses):
    guess_right = False
    for i in range(guesses):
        try:
            guess = int(input(f"{BLUE}[ ? ]{WHITE} Guess the number : "))
            if guess > random_pick:
                print(f"{RED}[ ! ]{WHITE} Your guess is high!")
            elif guess < random_pick:
                print(f"{RED}[ ! ]{WHITE} Your guess is low")
            else:
                print(f"{GREEN}[ $ ]{WHITE} You guessed it! Congratulations")
                guess_right = True
                break
        except ValueError:
            print(f"{RED}[ ! ]{WHITE} Wrong value, try again!")
    if not guess_right:
        print(f"{YELLOW}[ ! ]{WHITE} Better luck next time, the number was {random_pick}")

两种方案均可解决问题，方案1语法更简洁，属于Python的标准用法。

内容的提问来源于stack exchange，提问作者34598240