Wouldn't that become a 3-D cell-array of 1-by-2 arrays? Maybe something like this:
nested_list{1,1,1} = [1,1];
nested_list{1,1,2} = [2,2];
nested_list{1,2,1} = [3,3];
nested_list{1,2,2} = [4,4];
nested_list{1,2,3} = [5,5];
nested_list{2,1,1} = [1,1];
nested_list{2,1,2} = [2,2];
nested_list{2,2,1} = [3,3];
nested_list{2,2,2} = [4,4];
nested_list{2,2,3} = [5,5];
nested_list{3,2,3} = [6,6];
This would be very clean to index into after checking the nonemptiness of the cell-elements.
Or do you want a cell-array of cell-arrays of cell-arrays?
%Python list
row11 = {[1,1],[2,2]};
row12 = {[3,3], [4,4], [5,5]};
layer1 = {row11,row12};
row21 = {[1,1],[2,2]};
row22 = {[3,3], [4,4], [5,5]};
row22 = {[6,6]};
layer2 = {row21,row22};
nested_list = {layer1,layer2};
This becomes a mess to index into:
nested_list{1}{2}{3} % etc...
Then you'll have to check the type of each cell-element along the way, I'd try to avoid that hassle and try to stick with the first data-structure - since cell-elements can be whatever types you need I don't easily see the benefits of having cell-arrays nested too deep.
HTH
