How to sort a list/tuple of lists/tuples by the element at a given index?

Question

I have some data either in a list of lists or a list of tuples, like this:

data = [[1,2,3], [4,5,6], [7,8,9]]
data = [(1,2,3), (4,5,6), (7,8,9)]

Answer 1

Without lambda:

def sec_elem(s):
    return s[1]

sorted(data, key=sec_elem)