Python寻宝游戏中如何正确结束if else语句避免代码继续执行？

问题原因 #

你的代码里三组条件判断是完全平级的关系，哪怕前面已经触发了Game Over逻辑，程序也不会终止，还会继续执行后续的输入询问代码，甚至当你第一步选了right或者无效选项时，wait_or_swim变量根本没有被定义，运行到第二个判断块的时候还会直接触发变量未定义的报错。

修复方案 #

推荐用嵌套判断的写法，把后续步骤的逻辑全部封装到前一步选择正确的分支内，只要选错就不会进入后续逻辑，天然不会执行多余的代码，修改后代码如下：

print('Welcome to the Treasure Hunt!')
print('Your goal is to find the treasure.')
direction = input('You are at a crossroad. Where do you want to go? Type "left" or "right". \n').lower()

if direction == "left":
    wait_or_swim = input('You have come to a lake. There is an island in middle of the lake. Type "wait" to wait for a boat or "swim" to swim accross the lake? \n').lower()
    if wait_or_swim == "wait":
        color = input('You arrived at the island unharmed. There is a house with three doors. One red, one blue and one green. Which one will you choose? \n').lower()
        if color == "red":
            print('You fell into a room full of fire.\nGame Over.')
        elif color == "green": 
            print('Congratulations, you have found the treasure!')
        elif color == "blue":
            print('You fell into a ditch.\nGame Over.')
        else:
            print('You chose a door that does not exist.\nGame Over.')
    elif wait_or_swim == "swim":
        print('You have been eaten by a shark.\nGame Over.')
    else:
        print('You chose an option that does not exist. ')
elif direction == "right":
    print('You are crushed by a truck. Game Over!')
else:
    print('You chose an option that doesn\'t exist.')

如果你不想调整原有代码的结构，也可以在每一个Game Over的打印语句后加一行exit()直接终止程序运行，同样能实现需求。

内容的提问来源于stack exchange，提问作者Prab-mat