Python猜数字游戏while循环条件为false仍被执行问题求助

问题成因 #

• 逻辑混用错误：同时使用了while循环和递归两种重复执行逻辑，二者相互冲突。每次在循环内调用guess(lives-1)时，会进入新的函数递归层，上层函数的lives和guess_number变量不会被修改，递归层退出后，上层的while循环仍会按旧的变量值继续执行，导致lives为0的判断无法终止上层循环。
• 循环内未更新输入值：guess_number = int(input(...))写在了while循环外部，进入循环后永远不会重新读取用户的新输入，也不会更新lives变量的值，导致循环判断条件永远不会触发false退出。
• 猜对分支逻辑不可达：while循环的准入条件是guess_number!= number，因此循环内部的else: print(f"You got it...")分支永远不会被执行。

修复方案 #

方案1：改为纯循环实现（推荐） #

去掉递归逻辑，所有重复执行逻辑用循环实现，代码如下：

import random
print("Welcome to the Number Guessing Game!")
number = random.randint(1,100)
print("I'm thinking of a number between 1 and 100.")
# 调试用，正式运行可删除下一行
# print(number)

def set_lives():
    level = input("Choose a difficulty.Type 'easy' or 'hard': ")
    return 10 if level == "easy" else 5

def guess(lives):
    while lives > 0:
        guess_number = int(input("Make a guess: "))
        if guess_number == number:
            print(f"You got it! The answer was {number}")
            return
        elif guess_number > number:
            print("Too High")
        else:
            print("Too Low")
        lives -= 1
        if lives > 0:
            print(f"You have {lives} attempts remaining to guess the number")
        else:
            print("You are out of moves.You loose")
            print(f"The correct number is {number}")

guess(set_lives())

方案2：改为纯递归实现 #

如果要保留递归逻辑，就删除冗余的while循环：

import random
print("Welcome to the Number Guessing Game!")
number = random.randint(1,100)
print("I'm thinking of a number between 1 and 100.")
# 调试用，正式运行可删除下一行
# print(number)

def set_lives():
    level = input("Choose a difficulty.Type 'easy' or 'hard': ")
    return 10 if level == "easy" else 5

def guess(lives):
    if lives <= 0:
        print("You are out of moves.You loose")
        print(f"The correct number is {number}")
        return
    guess_number = int(input("Make a guess: "))
    if guess_number == number:
        print(f"You got it! The answer was {number}")
        return
    elif guess_number > number:
        print("Too High")
    else:
        print("Too Low")
    print(f"You have {lives-1} attempts remaining to guess the number")
    guess(lives-1)

guess(set_lives())

内容的提问来源于stack exchange，提问作者sumathi