如何在函数内比较字符串

Question

I am trying to learn Python for fun. I'm doing an online lesson at codecademy.com, but I have no idea what I have to do.

I'm trying to compare 's' parameter with other parameter (string parameter), and the returned value should be "Sorry".

def shut_down(s):
    return s
    if s == 'yes':
        return "Shutting down"
    elif s == 'no':
        return "Shutdown aborted"
    else:
        return "Sorry"

so I call the function:

shut_down('lhagvbs')

It always returns, "Your function failed on the message yes. It returned 'yes' when it should have returned 'Shutting down'"

And i think my code does not work. Not even the def function is correct.

Please explain why, what, where, etc.

Sorry, I do not speak/write English well, but I hope it's understandable.

(This is not homework).

Answer 1

You need to remove the return s as you are returning s regardless, all the code after return s is unreachable so you never evaluate your if/elif or else:

def shut_down(s):
    if s == 'yes':
        return "Shutting down"
    elif s == 'no':
        return "Shutdown aborted"
    else:
        return "Sorry"

In keeping with the fact you can only return once from any function, you can also forget the elif and else:

def shut_down(s):
    if s == 'yes':
        return "Shutting down"
    if s == 'no':
        return "Shutdown aborted"
    return "Sorry"