Hello, World!

I've been writing many snippets of code. Some snippets do what I consider really nifty things. Some other pieces were written while I was learning a language, a framework, or just having fun. Most of them are deleted...

Why not post them? Clean them up a bit, add a short explanation, or a long one if I can. Maybe I can get some constructive criticism, or perhaps it is useful for someone out there. Considering what I just said, I think that posting is one good incentive to keep learning languages and frameworks and computer programming in general.

So here goes a snippet. The merge sort algorithm developed using the divide and conquer strategy in python.

def merge(xs, ys):
    """
    takes two ordered lists and merges keeping the order
    >>> merge([1,3,5,8],[2,4,6,7])
    [1, 2, 3, 4, 5, 6, 7, 8]

    >>> merge([1,2,6,9],[-2,-1,6])
    [-2, -1, 1, 2, 6, 6, 9]

    >>> merge([-10,-2], [1,2,3,4,5,6,7,8])
    [-10, -2, 1, 2, 3, 4, 5, 6, 7, 8]
    """

    merged_list = []
    x_index, y_index = 0, 0

    while (x_index < len(xs)) and (y_index < len(ys)):
        x, y = xs[x_index], ys[y_index]
        if x <= y:
            merged_list.append(x)
            x_index += 1
        else:
            merged_list.append(y)
            y_index += 1
        

    return merged_list + (xs[x_index:] or ys[y_index:])

def merge_sort(xs):
    """ Divide and conquer strategy in merge sort """

    # Divide the problem
    half = len(xs) / 2
    
    # If the list is empty or singleton then it's ordered
    if len(xs) <= 1: 
        return xs
    else: # Conquer
        first = xs[0:half]
        second = xs[half:len(xs)]
        return merge(merge_sort(first), merge_sort(second))

if __name__ == '__main__':
    import doctest
    doctest.testmod()