How do I detect empty cells in a cell array?

Use CELLFUN

%# find empty cells
emptyCells = cellfun(@isempty,a);
%# remove empty cells
a(emptyCells) = [];

Note: a(i)==[] won’t work. If you want to know whether the the i-th cell is empty, you have to use curly brackets to access the content of the cell. Also, ==[] evaluates to empty, instead of true/false, so you should use the command isempty instead. In short: a(i)==[] should be rewritten as isempty(a{i}).