Find following values and represent them in a matrix

Hi! I have a matrix

A=[23 34 45 0 0 0;21 34 0 0 23 11;34 23 0 0 0 22;23 11 21 0 0 45;11 45 23 0 0 0]

I have found the unique values in the matrix:

U = unique(A) = [0 11 21 22 23 34 45]

Excluding the value 0, I want a matrix 6x6 (6 is the number of values found without zero) in which I want to represent the number of times that a value is following from another value in every row.

Eg

Occurence that after 11, there is 11 is zero

Occurence that after 11, there is 21 is 1

Occurence that after 11, there is 22 is zero

Occurence that after 11, there is 23 is zero

Occurence that after 11, there is 34 is zero

Occurence that after 11, there is 45 is 1

So the first row of the matrix I want is:

B = [0 1 0 0 0 1]

Occurence that after 21, there is 11 is zero

Occurence that after 21, there is 21 is 0

Occurence that after 21, there is 22 is 0

Occurence that after 21, there is 23 is 0

Occurence that after 21, there is 34 is 1

Occurence that after 21, there is 45 is 1

So the second row of the matrix is

B = [0 1 0 0 0 1; 0 0 0 0 1 1; ...]

I want to repeat the same process, for all the values in U.

I have no idea, I can do it

Can you help me? thanks

[Stephen23]

Are you sure that "Occurence that after 21, there is 45 is 1" ?

I don't see any occurrences of 45 after 21, anywhere in the matrix A.

Answer 1

[Stephen23]

A = [23,34,45,0,0,0;21,34,0,0,23,11;34,23,0,0,0,22;23,11,21,0,0,45;11,45,23,0,0,0];
[R,C] = ndgrid(unique(A(A~=0)));
fun = @(r,c)nnz( r==A(:,1:end-1) & c==A(:,2:end));
out = arrayfun(fun,R,C)

creates this:

 out =
     0     1     0     0     0     1
     0     0     0     0     1     0
     0     0     0     0     0     0
     2     0     0     0     1     0
     0     0     0     1     0     1
     0     0     0     1     0     0