函数和if - else在python中.Codeacademy

Question

编写一个函数shut_down,它接受一个参数(你可以使用你喜欢的任何东西;在这种情况下,我们使用s作为字符串).当shut_down函数获得"是","是"或"是"作为参数时,应该返回"关闭...",并且"关闭已中止!" 当它变为"否","否"或"否"时.

如果它得到的不是那些输入,该函数应该返回"抱歉,我不明白你."

这是我的代码到目前为止......它的错误并说"不"不会返回"关机中止!"

def shut_down(s):
    if s == "Yes" or "yes" or "YES":
        return "Shutting down..."
    elif s == "No" or "no" or "NO":
        return "Shutdown aborted!"
    else:
        return "Sorry, I didn't understand you."

Answer 1

这个:

s == "Yes" or "yes" or "YES"

相当于:

(s == "Yes") or ("yes") or ("YES")

这将始终返回True,因为非空字符串是True.

相反,您希望s单独与每个字符串进行比较,如下所示:

(s == "Yes") or (s == "yes") or (s == "YES")  # brackets just for clarification

它应该像这样结束:

def shut_down(s):
    if s == "Yes" or s == "yes" or s == "YES":
        return "Shutting down..."
    elif s == "No" or s == "no" or s == "NO":
        return "Shutdown aborted!"
    else:
        return "Sorry, I didn't understand you."

Answer 2

您可以通过以下几种方式实现:

if s == 'Yes' or s == 'yes' or s == 'YES':
    return "Shutting down..."

要么:

if s in ['Yes', 'yes', 'YES']:
    return "Shutting down..."