Sum of all odd and even arrays in matrix

Suppose I have a matrix a:

a = [2,3;1,2;1,2;0,1;1,2;3,1;1,3;2,1;2,3;3,1];

I want to build matrix b with dimension 2*2 that first row is sum up of all odd rows of matrix a and second rwo is sum up of all even rows of matrix a

b = [16;19]

[Image Analyst]

OK, suppose you do. Is this homework? This is very very simple. What have you tried?

[the cyclist]

Here is a hint. Do you know how to make a vector of odd numbers? Even numbers?

Answer 1

[Harry]

From your description, I think you want to do this:

b = [sum(a(1:2:end,:)); sum(a(2:2:end,:))]

However, I'm not sure why you wrote "b = [16;19]". If you want to get that, then just write:

b = sum(a).'