concatenate all cells in a celll array

hello i have a cell array 7x7

 Columns 1 through 6

    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]
    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]    [256x1 double]

Column 7

    [256x1 double]
    [256x1 double]
    [256x1 double]
    [256x1 double]
    [256x1 double]
    [256x1 double]
    [256x1 double]

I want to concatenate all t he cells in this cell array to a 7x7x256=12544x1 vector how do i do that ?

Answer 1

[Image Analyst]

Try this:

ca = ca{:}

[Newman]

it is returning 256x1 not 12544x1

[Image Analyst]

Then try using mat2cell(). Or just a simple for loop if you want

ca2 = [];
for k = 1 : numel(ca)
  ca2 = [ca2; ca{k}];
end

[Newman]

thanks

[Image Analyst]

You're welcome, though you should really not even use cell arrays in the first place. They are for using mixed data types (though this has been supplanted by the new "table" data type in most cases), or for arrays of strings of different lengths. They were not meant for arrays of simple numerical arrays, which could be handles by a simple 2D numerical array in your case.

Answer 2

[Azzi Abdelmalek]

a=arrayfun(@(x) rand(256,1),ones(7),'un',0)
out=reshape(cell2mat(a),[],1)

[Image Analyst]

Thanks Azzi, I knew there had to be a way.

I think the original poster should not even have used a cell array in the first place. Since all cell contents were double arrays, he should have just used a simple numerical matrix and not mess around with cell arrays.

[Azzi Abdelmalek]

Image Analyste I don't understand the thanks for what? but I agree with you that some choices are really incomprehensible!

[Image Analyst]

Well, you used reshape() and I did the "for" loop. While a for loop might be easier for beginners to understand, reshape() is possibly the more "MATLAB-ish" way to do it. And it can be complicated/confusing to figure out when to use brackets, braces, and parentheses with cell arrays, even for us experienced people that's why I recommend beginners to avoid them if they can.