finding the frequency of each row (2)

Hello all,

Per my previous question, I have several mx2 matrices with rows from (0,1), (-1,0), (0,1), (0,-1), (1,1), (-1,1), (1,-1),(-1,-1) and I would like to find the frequency of each of above coordinates, I used unique and hisc to give me the frequency of each row. Now, since I would like to compare different matrices, I would like for each matrix have a corresponding output of 8 rows, where each row indicates the number of times that each of above coordinates appear. In particular, if e.g (0,1) is not among the rows of my matrix, I would like to see zero frequency.

For instance, if A=[1 1; 0 1; 1 0; -1 1;-1 1;0 1;0 1]

I would like to see something like:

    -1    -1   0
    -1     0   0
    -1     1   2
     0    -1   0
     0     1   3
     1    -1   0
     1     0   1
     1     1   1

Is there a way to do it? Thanks.

Answer 1

[Azzi Abdelmalek]

B=[-1    -1
  -1     0
  -1     1
   0    -1
   0     1
   1    -1
   1     0
   1     1]
A==[1 1; 0 1; 1 0; -1 1;-1 1;0 1;0 1]
[ii,jj,kk]=unique(A,'rows')
f1=histc(kk,1:numel(jj)); 
f=zeros(size(B,1),1);
idx=ismember(B,ii,'rows');
M=[B zeros(size(B,1),1)];
M(idx,:)=[ii f1]

Answer 2

[Walter Roberson]

You can get the counts using accumarray(A + 2, 1, [3 3])