count the number of transitions from 0 to 3 in cells in cell array

Hi.

I have a cell array containing 1000 cells. in each cell there is a matrix with different number of rows but with 50 columns.

the rows contains number from 0-3. I want to count how many times a 0 is followed by a 3 in each column.

Below you can see the code that I used to count the total number of transitions, from any number to another. Is there an easy way to change this code so that it counts the number of transitions from a certain number to another?

x=numel(CA)
newCA=cell(x,1);
for i=1:x
     newCA{i}=sum(diff(CA{i})~=0);   
end

Answer 1

[Stephen23]

Here is a simple method based on logcal arrays, demonstrated on two Nx4 matrices in a cell array. The first matrix has two 0,3 transitions, the second matrix has three.

>> C = {[0,1,2,3;0,3,0,3;0,2,0,1],[0,3,1,2;3,2,1,0;3,0,3,0;3,0,3,3]};
>> C{:}
ans =
   0   1   2   3
   0   3   0   3
   0   2   0   1
ans =
   0   3   1   2
   3   2   1   0
   3   0   3   0
   3   0   3   3
>> F = @(m) nnz(m(:,1:end-1)==0 & m(:,2:end)==3);
>> V = cellfun(F,C)
V =
   2   3
>> N = sum(V)
N =  5

[merialu]

Hi,

Thank you for a quick answer. this works great but i realize that i was not clear in my question.

With this solution I get the number of transitions from 0 to 3 for each cell. is it possible to get it for each column in each cell?

since I have 50 columns in each cell i would like the answer to consist of 50 answers in each cell.

[Stephen23]

>> C = {[0,0,0,0;3,1,2,0;0,0,3,1;3,3,0,1],[1,1,0,3;0,3,3,3;3,3,3,0]};
>> C{:}
ans =
   0   0   0   0
   3   1   2   0
   0   0   3   1
   3   3   0   1
ans =
   1   1   0   3
   0   3   3   3
   3   3   3   0
>> F = @(m) sum(m(1:end-1,:)==0 & m(2:end,:)==3, 1);
>> D = cellfun(F,C,'uni',0);
>> M = vertcat(D{:}) %  for each matrix
M =
   2   1   0   0
   1   0   1   0
>> sum(M,1)          % for all matrices
ans =
   3   1   1   0

[merialu]

Yes, perfect!

Thank you for your help, really appriciate it.