MATLAB: Remove rows with all zeros

Question

I have

 a =
     1     2     3
     0     0     0
     2     1     0
     4     5     0
     0     0     0
     2     0     1

I need

 b=
     1     2     3
     2     1     0
     4     5     0
     2     0     1

Answer 1

b = a(any(a,2),:);