Concatenate Cellarray and cell2mat

I have a 7x3 Cell array of cells as follows:

X =

    [  20]    [  20]    [  20]
    [ 125]    [ 315]    [ 125]
    [ 224]    [ 500]    [ 200]
    [1000]    [1000]    [ 250]
    [2000]    [2000]    [ 500]
        []        []    [1000]
        []        []    [2000]

I need to concatenate this to a 1 column cellarray and eventually convert it to a matrix. Any help is greatly appreciated!

Please note that equalizing the dimension by filling in the empty arrays with zero is not an option for me.

Answer 1

[Walter Roberson]

arrayfun(@(IDX) [X{IDX,:}], 1:size(X,1), 'Uniform', 0)

Answer 2

[Sean de Wolski]

How about a for-loop with cell2mat on each row?

Xv = cell(size(X,1),1);
for ii = 1:length(X)
  Xv{ii} = cell2mat(X(ii,:));
end

Answer 3

[Aviator]

I just figured it out, "reshape" does the job. this is one of the answers though. Thanks everybody for responding....

[m,n] = size(X); XMatrix = cell2mat(reshape(X,m*n,1));

[Sean de Wolski]

for that case you could just do:

Xmatrix = [X(:)]

[Walter Roberson]

This depends on what is meant by a one-column cell array. The code I showed produces a one-column cell array (or a one-row, whichever), in which the cells happen to be different sizes. Creating a vector out of all of the elements of the array would be a different task, and there would not usually be a lot of point in producing a "one column cell array" of the result when a numeric vector result would do.

The code posted in this Answer does not satisfy the initial condition that the result be a one-column cell array: you would need to wrap the results inside {} in order to get a cell array, or use mat2cell() on it. But if you are going to use mat2cell then you might as well just use

X(cellfun(@isempty,X)) = [];

and that would be enough, including the conversion to column vector.

[Jan]

Btw.: cellfun('isempty', X) is much faster than cellfun(@isempty, X).