Perform an action over 2 and 2 elements in a list

Question

I have a list of numbers, say

data = [45,34,33,20,16,13,12,3]

I'd like to compute the difference between 2 and 2 items, (that is, for the above data I want to compute 45-34,33-20,16-13 and 12-3, what's the python way of doing that ?

Also, more generally, how should I apply a function to 2 and 2 of these elements, that is, I want to call myfunc(data[0],data[1]),myfunc(data[2],data[3]) and so on over the list.

Answer 1

Try slicing the list:

from itertools import izip
[myfunc(a, b) for a, b in izip(data[::2], data[1::2])]

or you can use the fact that izip guarantees the order in which it consumes its arguments:

idata = iter(data)
[myfunc(a, b) for a, b in izip(idata, idata)]