Question

ps9#2: quick question.

for part #2 we have to write addShape to our shape set.

My thinking is that I would test with an if statement to verify that the argument passed to the addShape is in fact a valid shape. What's odd is that the program works when I'm limited just to circles.

however when I use an if statement with 'or' for circle,square,triangle, I get an error.

can anyone explain what's going on?

here's the circle example

http://codepad.org/LK04Deey

here's the circle, square, triangle example where I get a type error.

http://codepad.org/T0bXeVGk

Answer 1

maybe try the isinstance() function instead -
http://docs.python.org/library/functions.html#type

Answer 2

I figured it out.

It was kinda obvious.

I think if only takes one comparison/equality. You can't use 'or' within the if statement.

http://codepad.org/kTzrKgPa

Answer 3

http://dpaste.com/699312/

Answer 4

you should be able to use multiple expresions (that evaluate to a boolean) seperated be or or and in an if statement - http://dpaste.com/699316/

Answer 5

ah. I got my equalities screwed up. I need an 'and' statement instead of an 'or' statement.

if it's the case that they are all 'not equal', then I don't have a valid shape.

Thanks.

Answer 6

or use or with == instead of !=
http://dpaste.com/699319/

Answer 7

and using isinstance is easier if they are all subclasses of the same class
http://dpaste.com/699332/

Answer 8

thanks for all the feedback bwCA. really helps my understanding.