Question

I’m trying to write some code that can sum elements inside a list that looks like the following example:

list[(a,b,1),(c,d,2),(e,f,3)]

What I want to do is to sum the numbers inside this list. What is the name of such kind of lists?

Hope you can help me.

Answer 1

Given a list, and assuming you have to sum integers as given in the example

foo = [('a','b',1),('c','d',2),('e','f',3)]

You can do the following

sum(e for e in itertools.chain(*foo) if isinstance(e, int))

• Here itertools.chain would flatten the list
• isinstance checks if the element is an instance of integer
• sum only those elements which is an instance of int

Incase if the number elements are at a defined index, as in the example, you can do

>>> zip(*foo)
[('a', 'c', 'e'), ('b', 'd', 'f'), (1, 2, 3)]
>>> sum(zip(*foo)[2])
6