2D Matrix Operation

Hello,

 I have an input array 
A = [  8 4; 
  3 6; 
  2 7; 
  1 4; 
  2 3;
  2 1;
  3 1; 
  3 5; 
  8 6; 
  8 1];

I have 2 entries [8 4] and [1 4] .Now i want only [1 4] to be retained as this is minimum of two. Similarly i have three entries [2 1] [3 1] and [8 1].Out of these i want to retain only [2 1] as that is the minimum of these three eternities. Also i have two entries [3 6] and [8 6]. Out of these i want to retain only [3 6] as this is the minimum of the two entries. Final output i want is

Res=

    [1 4;
     2 1;
     2 7;
     3 5;
     3 6];

Please Let me know how this is done.

 Looking forward to hear from you.

Thanks

Pankaja

Answer 1

[Andrei Bobrov]

t = accumarray(A(:,2),A(:,1),[],@min);
out = sortrows([t(t>0),unique(A(:,2))]);