Deleting empty rows in a 3D Cell Array in MatLab

Question

Luiz 2013-4-22

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/73164-deleting-empty-rows-in-a-3d-cell-array-in-matlab

I have a large 3D CELL ARRAY (x1) which I have to delete the empty rows. How can I do this?

Example of my cell array (some pieces of the variable):

      val(:,:,1) = 
      [20]    []    []    []    []    []    
      [ 0]    []    []    []    []    []    
      [ 0]    []    []    []    []    []    
      []      []    []    []    []    []   
      (...)
      val(:,:,42) = 
      [ 34225]    [   215]    [    0]    [   0]    [    0]    [    0]      
      [ 85200]    [   545]    [    0]    [   0]    [    0]    [    0]      
      [ 65074]    [   190]    [ 1000]    [   0]    [    0]    [    0]        
      [ 81570]    [  1385]    [ 2475]    [   0]    [    0]    [    0]            
      [ 67236]    [   530]    [  365]    [   0]    [    0]    [    0]        
      [ 61338]    [     0]    [  100]    [   0]    [    0]    [    0]        
      []          []          []         []        []         []                  
      []          []          []         []        []         []                 
      []          []          []         []        []         []

In this case, I want to exclude the 4th row of `(:,:,1)`, the three last rows from `(:,:,42)` and all the others from these variable.

I've tried

    x1(all(all(cellfun((@isempty,x1),2),:,:) = [];
But it gave me this following error:

Error: Expression or statement is incorrect--possibly unbalanced (, {, or [.

PS: I cannot use `"=="` because its a cell array.

Thanks in advance

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Cedric 2013-4-22

编辑：Cedric 2013-4-22

You cannot erase the 4th row of val(:,:,1) without erasing as well the 4th row for all valid 3rd indices. In your example, doing this would erase val(4,:,42) as well.. is it what you want to do?

Also, your example should show that val(:,:,1) and val(:,:,42) have the same size (for val to be a 3D cell array). Are you sure that you don't have a cell array of 2D cell arrays? (you index val as a 3D cell array though)

Luiz 2013-4-23

Wow, thats bad, because I want to erase ONLY the empty rows. Yeah, they have the same size, coincidently ! I'm sure I got a 3D Cell Array !

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Answer 1

Cedric 2013-4-23

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https://ww2.mathworks.cn/matlabcentral/answers/73164-deleting-empty-rows-in-a-3d-cell-array-in-matlab#answer_83155

在 MATLAB Online 中打开

If you want to be able to remove rows from single "pages", you should use a cell array of cell arrays, e.g.

 A = cell(3, 1) ;
 A{1} = {2, 3, 4; [], [], []; [], 5, []} ;
 A{2} = {9} ;
 A{3} = {2, 3, 4, 5, 6; [], 9, [], [], []; ...
         [], [], [], [], []; [], [], [], [], []} ;
 for k = 1 : length(A)
    id = all(cellfun(@isempty, A{k}), 2) ;
    A{k}(id,:) = [] ;
 end

After execution, we get:

 >> A{1}
 ans = 
    [2]    [3]    [4]
     []    [5]     []
 >> A{2}
 ans = 
    [9]
 >> A{3}
 ans = 
    [2]    [3]    [4]    [5]    [6]
     []    [9]     []     []     []