How to keep certain numbers in a cell array?

Lets say for example I have a cell array A = {1,2,3},{4,5,6},{7,8,9},{10,11,12}. I am then given the string B = [1,3,5,12]. How would I create an output cell array where the numbers which were not mentioned in the string B were removed? i.e ans = {1,3} {5} {12}

Thank you for your time

Nabil

[Jan]

What have you tried so far? Which problems occur?

A = {1,2,3},{4,5,6},{7,8,9},{10,11,12}

This is not a cell array and no valid Matlab code. Please do not let use guess which input you have. Is this:

A = {[1,2,3], [4,5,6], [7,8,9], [10,11,12]}

or

A = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}}

?

[Nabil Abdullah]

my bad its the second one, A = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}}, also the ans would be {{1,3},{5},{12}}

I have tried doing the below:

y = {};
for i = 1:length(A)
    C = A{i}    
    for j = B
        if length(intersect(B,C)) == 1
            y{end+1} = {intersect(B,C)}
        end
    end
end

Answer 1

[Jan]

A = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}};
B = [1,3,5,12];
R = cell(size(A));
for iA = 1:numel(A)
  v     = cat(2, A{iA}{:});   % A{iA} as vector
  ex    = ismember(v, B);
  R{iA} = A{iA}(ex);
end
R = R(~cellfun('isempty', R));

Or:

R  = cell(size(A));
iR = 0;
for iA = 1:numel(A)
  v  = cat(2, A{iA}{:});   % A{iA} as vector
  ex = ismember(v, B);
  if any(ex)
    iR    = iR + 1;
    R{iR} = A{iA}(ex);
  end
end
R = R(1:iR);

[Nabil Abdullah]

I see, I'm not familiar with the ismember function. If you dont mind me asking, would the above code still work if A = {[1,2,3], [4,5,6], [7,8,9], [10,11,12]}? and what would I have to change if I wanted the output ans = {[1,3] [5] [ ] [12]}? is this even possible

[Jan]

To keep the empty matrix in the output, remove the "R = R(~cellfun(..." line from the 1st code. You can try by your own, if the code works for the wanted input.