matrix - Using a Vector as Indices in Octave -

let's have 1 matrix , 1 vector. possible use values in vector indices select 1 value each row in matrix? here's example of accomplish:

a = [1, 2, 3;      4, 5, 6;      7, 8, 9;]  b = [1;3;1]  c = a(b) or c = a(:,b)   leading   c = [1; 6; 7] 

of course loop bigger matrices take while. use make logical matrix in following fashion:

a = zeros(3,3)  b = [1;3;1]  a(b) = 1  = [1, 0, 0;      0, 0, 1;      1, 0, 0] 

thanks advice able give me.

you need create linear indices that. following example:

octave-3.8.2> = [1  2  3                    4  5  6                    7  8  9]; octave-3.8.2> b = [1 3 1]; octave-3.8.2> ind = sub2ind (size (a), 1:rows (a), b); octave-3.8.2> c = a(ind) c =     1   6   7