Python代码无论输入如何都执行if语句、不触发elif分支问题求解

问题根因 #

代码中的逻辑运算符or使用不符合语法规则，Python中or连接的是两个独立的布尔表达式：
你写的if ans1 == 'Yes' or 'Y'实际执行逻辑为：

先判断ans1 == 'Yes'的布尔结果，再判断'Y'的布尔值
非空字符串的布尔值恒为True，所以无论用户输入什么内容，整个if条件的判断结果永远为True，永远会进入if分支，不会触发elif逻辑。

修复方案 #

有两种常用的修正写法，任选其一即可：

写法1：补全所有判断条件 #

把or两侧的判断都补全为完整的布尔表达式：

if ans1 == 'Yes' or ans1 == 'Y':
    print("You have gained 1 point")
elif ans1 == 'No' or ans1 == 'N':
    print(" You have chosen to leave the coin.")
    print("You did not gain a point.")

写法2：使用成员运算符简化判断 #

用in判断输入是否在目标值集合里，代码更简洁易读：

if ans1 in ('Yes', 'Y'):
    print("You have gained 1 point")
elif ans1 in ('No', 'N'):
    print(" You have chosen to leave the coin.")
    print("You did not gain a point.")

优化建议（可选） #

可以在接收输入时顺便去除首尾空格、统一大小写，兼容用户的不规范输入：

# 去除首尾空格后统一转大写，匹配时就不用区分用户输入的大小写
ans1 = input("Will you take the coin? Yes or No?").strip().upper()
if ans1 in ('YES', 'Y'):
    print("You have gained 1 point")
elif ans1 in ('NO', 'N'):
    print(" You have chosen to leave the coin.")
    print("You did not gain a point.")

完整修正后代码 #

print("Treasure Quest")  
print("------------")  

name = input("What is your name traveler?") 
print(f"Your game name for this game is: {name}")

goldCoin = "Take this gold coin, it's rare!"  
ans1 = input("Will you take the coin? Yes or No?").strip()
if ans1 in ('Yes', 'Y'):
    print("You have gained 1 point")
elif ans1 in ('No', 'N'):
    print(" You have chosen to leave the coin.")
    print("You did not gain a point.")

内容的提问来源于stack exchange，提问作者Dancing Mudkipz