create a new matrices by using existing matrices

Hi,

I try to create a new matrices by using specific condition from existing matrices(its a data file) for example I have

a= [1,2,10;
    1, 3, 20;
    1, 4, 5;
    1, 5, 7;
    2, 3, 3;
    2, 4, 1;
    2, 5, 3;
    3, 4, 6;
    3, 5, 4;
    4, 5, 8];

(first and second column are points and third one is the distance of each other) I want point number 2, 3 and 4 in the new matrices (those numbers (x) are come from another matrices(y) which are index of zeros)

x=find(y==0);

result supposed to be (just those numbers, not all of them)

b=[2,3,3;
   2,4,1;
   3,4,6];

not like this

b=[2,3,3;
   2,4,1;
   2,5,3;
   3,4,6
   3,5,4];

I am sorry if i cant explain well or it seems like do for me. I appreciate for some tip

Answer 1

[Vivek Selvam]

Hope this helps.

x      = a(:,1)
y      = a(:,2)
want   = [2 3 4]
choose = ismember(x,want) & ismember(y,want)
a(choose,:,:)