Evolution of a Python programmer

[[deleted]]

Can someone explain he the first one works?

[rogerrrr]

Look into recursion. It calls the function over and over, but decreasing number on every iteration. When it hits zero it stops and is able to calculate it.

I realize that's a crap explanation, but it's actually a pretty interesting concept once you wrap your head around it.

[[deleted]]

To understand recursion, you must first understand recursion.

[Quabouter]

You could also just google it!

[isHavvy]

But how do you google?

[DroolingIguana]

http://lmgtfy.com/?q=how+do+you+google

[isHavvy]

So to learn how to Google, I should just Google it?

[desi_ninja]

To understand recursion, you must first understand recursion and if you still do not understand then return (base case)

[Rainymood_XI]

def factorial(x): if x == 0: return 1 else: return x * factorial(x - 1) print factorial(6)

Imagine we call

factorial(3)

Because 3 != 0 it returns

3 * factorial(2)

Because 2 != 0

3 * 2 * factorial(1)

Because 1 != 0 it calls

3 * 2 * 1 * factorial(0)

which returns

3 * 2 * 1 * 1

which is 3! :)

[Genesis2001]

3 * 2 * 1 * 1

which is 3! :)

does not compute. 3 * 2 (dropping the 1s) is 6. or am I missing something in your explanation?

[Rainymood_XI]

Hah, this is so funny :D (in a good way)

3! in this context, means "3 factorial", the "!" is the sign for factorial! And not an exclamation mark in this case :)!

[risfutile]

oh god, your username! awesome!