Python中if/else语句匹配列表元素失效问题求助

你的代码核心问题是字符串和列表的比较逻辑错误：user_answer是用户输入的单个字符串，而你用==将它和包含多个字符串的列表male/female做比较，字符串和列表永远不可能相等，所以无论输入什么都会进入else分支。

修正后的代码 #

把判断条件里的==改成in，检查输入的字符串是否存在于对应列表中：

user_answer = input("are you a male, or a female?:")
male = ["male", "Male", "MALE"]
female = ["female", "Female", "FEMALE"]
if user_answer in male:
    print("oh well thats awesome to hear! hello sir!")
elif user_answer in female:
    print("oh sick, nice to meet you miss")
else:
    print("im sorry, but that is not a valid entry")

更简洁的优化方案 #

可以把用户输入统一转为小写（同时去掉前后空格），这样不需要枚举所有大小写情况，代码更简洁鲁棒：

user_answer = input("are you a male, or a female?:").strip().lower()
if user_answer == "male":
    print("oh well thats awesome to hear! hello sir!")
elif user_answer == "female":
    print("oh sick, nice to meet you miss")
else:
    print("im sorry, but that is not a valid entry")

内容的提问来源于stack exchange，提问作者Robert Gibbons