MATLAB: New Vectors from Old Array

Question

I have a [50,6] set of data, and need to create two column vectors from it based on whether a piece of data in column 4 has a value or just 0. so if it has a value it returns the first column number that are in column 1, which correspond to the value or the 0. hopefully that make sense.

ex. a =

1 2 5 0

2 9 3 3

3 8 2 0

i need it to return

b = [2]' and c = [1,3]'

Answer 1

isz = a(:,4) == 0;
b = a(~isz, 1);
c = a(isz, 1);