Make me beautiful (code needs help)

[Sean 'Shaleh' Perry]

> 
> Here's my current code:
> 
> for i in range(len(data["A"])):
>      try:
>           data["new"].append(data["A"][i] - data["A"][i-1])
>      except OutOfBounds:
>           data["new"].append("?")
> 
> Now, the other problem, is that in general, I want to fill data["new"] with 
> an arbitary function of the values in data["A"].  As a dumb example, I 
> might want to fill data["new"] with copies of the mean (average) of 
> data["A"].  So, in some cases, the new values are relative to the current 
> location (ie i and i-1) and in other they are absolute (ie all of them).
> 
> I can certainly hack through this, but I'm looking for something pretty.  I 
> know python is up to it.
> 

why isn't data['new'][0] == 0?  How can there be a difference between [0] and
[-1]?

def successive(the_list, place):
    if place == 0: return 0
    return the_list[place] - the_list[place - 1]

for i in range(1, len(data['A'])):
    data['new'].append(successive(data['A'], i))