How to run and check this code? (Python basics)

Question

Basically, my question is about how to run this code? Finding the second smallest number from the given list using divide-and-conquer. I tried with print..But it gives me nothing. Just wanna see how this code works. Sorry for simple question, totally New in Python.

Answer 1

Well, just use a function call to run it, and a print to print it:

def two_min(arr):
    n = len(arr)
    if n==2: # Oops, we don't consider this as comparison, right?
        if arr[0]<arr[1]:                   # Line 1
            return (arr[0], arr[1])
        else:
            return (arr[1], arr[0])
    (least_left, sec_least_left) = two_min(arr[0:n/2])
    (least_right, sec_least_right) = two_min(arr[n/2:])
    if least_left < least_right:            # Line 2
        least = least_left
        if least_right < sec_least_left:    # Line 3
            return (least, least_right)
        else:
            return (least, sec_least_left)
    else:
        least = least_right
        if least_left < sec_least_right:    # Line 4
            return (least, least_left)
        else:
            return (least, sec_least_right)


print two_main([12,2])

If you'd like to know how this works, you can take a look at the online python visualizer. Link.