remove empty cells in MATLAB

Question

I want to remove all empty cells at the bottom of a matlab cell array. However all code example that I found collapse the matrix to a vector, which is not what I want.

So this code

a = { 1, 2; 3, 4; [], []}
emptyCells = cellfun('isempty', a); 
a(emptyCells) = []

results in this vector

a = [1] [3] [2] [4]

But I want instead this array

a =

[1]    [2]

[3]    [4]

How would I do that?

Answer 1

If you want to delete all the rows in your cell array where all cell are empty, you can use the follwing:

a = { 1, 2; 3, 4; [], []}
emptyCells = cellfun('isempty', a); 

a(all(emptyCells,2),:) = []

a = 
    [1]    [2]
    [3]    [4]

The reason it didn't work in your formulation is that if you index with an array, the output is reshaped to a vector (since there is no guarantee that entire rows or columns will be removed, and not simply individual elements somewhere).

Answer 2

This works for me:

a = { 1, 2; 3, 4; [], []};
emptyCells = cellfun('isempty', a);
cols = size(a,2);
a(emptyCells) = [];
a = reshape(a, [], cols);

but I'm not sure if it will be general enough for you - will you always have complete rows of empty cells at the bottom of your array?