how to remove duplicate matrixes in a cell array?

Question

I have a cell matrix TILER that include some matrix with different sizes.

TILER=[22x4 double]    [1265x4 double]    [58x4 double]    [31x4 double]     [58x4 double]

and we know that some matrixes are duplicate, for example [58x4 double] matrix. how can we remove duplicate matrixes from a cell array to have :

TILER=[22x4 double]    [1265x4 double]    [58x4 double]    [31x4 double]

here is a link, but it doesn't work

Answer 1

In this case it's hard to avoid loops. You can go along the following lines:

ind = true(1,numel(TILER)); %// true indicates non-duplicate. Initiallization
for ii = 1:numel(TILER)-1
    for jj = ii+1:numel(TILER)
        if isequal(TILER{ii}, TILER{jj})
            ind(jj) = false; %// mark as duplicate
        end
    end
end
TILER2 = TILER(ind);

Some optimizations are possible. For example:

• In the inner loop don't consider values that have been detected as duplicates in a previous iteration of the outer loop.
• Do a first check for equality of matrix sizes (this can be done efficiently with bsxfun), and then only test for equality between matrices that have the same size.

Answer 2

You can also manipulate it into a cell of strings and take advantage of the 'unique' command; starting with a cell 'a' of matrices:

b=cell(0);
for i=1:length(a), cat(2,b,mat2str(a{i}));, end
b=unique(b);
c=cell(0);
for i=1:length(b), cat(2,c,eval(b{i}));, end

Answer 3

If sizes could be considered a valid criteria for identifying duplicates in a cell array and the number of dimensions are consistent across the cell array elements, you may use this -

t1 = cellfun(@size,TILER,'uni',0) %%// TILER is your input cell array
t2 = vertcat(t1{:})
t3 = squeeze(reshape(bsxfun(@eq,t2,permute(t2,[3 2 1])),numel(t2),[],size(t2,1)))
[~,p2] = unique(t3','rows','stable') %%//'
TILER = TILER(p2)

Answer 4

Thank You Luis Mendo for providing us with your answer.

I slightly modified your version and better suits my needs. my data is a cell of cells i.e.

for kk = 1 : length(cellOfCells)
    TILER = cellOfCells{kk};
    ind = true(1,numel(TILER)); %// true indicates non-duplicate. Initialization
for ii = 1:numel(TILER)-1
    for jj = ii+1:numel(TILER)
        if size(TILER{ii},1) ~= size(TILER{jj},1)
            continue
        else
        membership = (ismember(TILER{ii}, TILER{jj},'rows'));

            if sum(membership)==size(TILER{ii},1)
                ind(jj) = false; %// mark as duplicate
            end
        end
    end
end
TILER2{kk} = TILER(ind);
end