Cell contents reference from a non-cell array object, why?

Hello there, ellipse_l is a cell array and each element is also a cell array with a certain number of structs in it. Why do I get the error shown in the headline?

Greets!

X0_r = cell(length, 1);

for i = 1:(numel(find(~cellfun(@isempty, ellipse_l))))
    for j = 1:(numel(find(~cellfun(@isempty,  ellipse_l))))

        X0_r{i}{j} = ellipse_r{i}{j}.X0;

      end
  end

Answer 1

[James Tursa]

As written, X0_r is a cell array, but the elements of this cell array are NULL (empty) since nothing has been put into it yet. So in this expression:

X0_r{i}{j}

you are trying to access the j'th element of a cell array, but there is no such cell array in that spot. That is, X0_r is a cell array but X0_r{i} is not a cell array since it is NULL (empty). So that {j} part attempts to access X0_r{i} as if it were a cell array which it isn't.

[Payjay]

I am sorry, the error occured because the first two elements X0{1 and 2} were empty.. this was a stupid question! Thanks anyways!

Answer 2

[Image Analyst]

length is is a built in function, so this doesn't make sense

X0_r = cell(length, 1);

Try this instead:

X0_r = cell(size(ellipse_l));
celldisp(ellipse_1); % Display it to verify it looks good.
celldisp(X0_r); % Display it to verify it's blank and the same size as ellipse_l.