Question

In lecture 4, when Prof Grimson adds spiders into the barnyard problem and shows us the barnyard2 and solve2 codes, I can see that solve2 doesn't have any return command. How come it runs through without any error?

Answer 1

You don't actually *need* a return statement for a function to work. The simplest function you can define does nothing at all actually, for instance:

def function():
pass

(the "pass" keyword is used for syntactical purposes; it does precisely nothing, but you still need it in this case because a function definition needs to have a body)

You could call this function, and it would be executed without any error, but it'd do nothing.

Going back to prof Grimson's function: it still is useful because it prints out the answer. You couldn't do something with it (for instance assigning the result to a avariable and do something with it), but it still gives you the right answer, so it's ok.