creating partition of sets

I am getting error, can anyone correct it please. Thanks in advance.

%A partition of a set A is a finite or infinite collection of nonempty, mutually disjoint subsets whose union is A.
A = [0, 1, 2, 3, 4]

C = {}; D = []; 
j = 1; 
while j < 10
    P = input('Enter INTEGERS with [ ] around them');     
    D = cell2mat(C)
     if  ismember(P,A) == ones(1,length(P)) && ismember(P,D) ~= ones(1,length(D))       
             C{(end+1)} = P;            
        else
            disp('Entered wrong, Please Enter correct one\n');
            j = j;
            
      end
      j = j + 1;     
        
end  

Answer 1

[Walter Roberson]

     if  ismember(P,A) == ones(1,length(P)) && ismember(P,D) ~= ones(1,length(D))

P is a vector. ismember() is going to return a vector the same length. == comparison to ones is going to return a vector the same length. You cannot use && with vectors

You could perhaps replace the first test with

if all(ismember(P, A))

Your second test is harder to make sense of as your documentation does not make clear what you want to have happen if some entries match but others do not. I seem to be having difficulty translating your documentation as to what the program is intended to do or how it is intended to do it.

My guess:

if all(ismember(P, A)) && ~any(ismember(P, D))

[k khaja]

To create a partition, first I have to check the main set A, whether all are from this set and second test will check whether the same elements already choosen for any other other partion C, and I converted C to single matrix D for comparison purpose.

Thanks a lot Walter, your guess is right and It worked, this is what I want.