how to concatenate a result of a loop to a single 2D mtrixa

Hi, I have the following code to find the linear index and the associated values of connected points in a matrix

a=[0 1 1 0 0 0
   1 1 1 0 2 2
   0 0 0 0 2 2
   0 0 0 0 0 0]
a_connected=bwlabeln(a);
%region properties of matrix a
cc2=bwconncomp(a_connected);
stats_a=regionprops(cc2,'pixellist','pixelidxlist');
% Extracting the connected objects and their index information
% For Test Matrix
arr_test=[];
tss=[];
for k=1:numel(stats)
    idx_test=stats(k).PixelIdxList;% gives linear index
    Pixels_in_region_test=test_connected(idx_test);% associated val
   arr_test=[idx_test,Pixels_in_region_test]  
end                            
I want to create an output matrix that will store the result of loop but so far been unable. the matrix only stores the value from the final iteration of the loop. I have used cat but it does  not work.
Any ideas on how to or what i am doing wrong?
Thanks

Answer 1

[Romendra]

okay, so the cat function does not work in this case but the vertcat sure did. Just added a little if loop in this

arr_test=[];
tss=[];
for k=1:numel(stats)
idx_test=stats(k).PixelIdxList;
Pixels_in_region_test=a_connected(idx_test);
if k==1
arr_test=[idx_test,Pixels_in_region_test]
else
tss=[idx_test,Pixels_in_region_test]
arr_test=vertcat(arr_test,tss)
end
end