Question

def ask():
    global name, loca

    print "What's your name?"
    name = raw_input('> ')
    print "Where are you from?"
    loca = raw_input('> ')

    if name or loca == None:
        print "Please enter valid details."
        ask()

ask()
print "Alright, so you're " + name + ", from " + loca + "."

With this script, it will only ever print the last line if both of my variables are empty. If I fill in one, or both, it triggers that if, making me redo the function.

What am I doing wrong here?

Answer 1

You have very well isolated the problem:

if name or loca == None:

Here you think it says:

"If either name or loca equal none:"

But instead it says:

"if (name) is true or (loca equals None) is true:"

Where it should say:

"if (name equals none) is true or (loca equals none) is true:"

Which is:

if name is None or loca is None:

See, by the way, that None comparisons are better carried out with is, since there is only one None object.

Also, a more pythonic way of doing it is:

if not all((name, loca)):

Or, seeing as “all” it’s just 2 variables:

if not (name and loca):

If you don’t understand, read around a bit (the Python tutorial is excellent — go for the conditionals part). Good luck!