change Index of non-zero values in 3D array

Question

lucksBi 2017-3-11

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/329307-change-index-of-non-zero-values-in-3d-array

评论： lucksBi 2017-3-12

HI.. I have a 3D array like this:

val(:,:,1) =
   0     0     0     0
   0     0     0     0
   0     0     0     0
  22     0     0     1
   0     0     0     0
   0    -1     0     0
   0     0    -1     0
   0     0     0     0
   0     0     0     0
   0     0     0     0

The problem is that i want all values to be in same row. e.g. in val(:,:,1) it should be 33,22,-1,-1,1 in 6th row of matrix. Is there any way to do this? I am new to matlab so sorry if my question sounds awkward.

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Answer 1

the cyclist 2017-3-11

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https://ww2.mathworks.cn/matlabcentral/answers/329307-change-index-of-non-zero-values-in-3d-array#answer_258275

编辑：the cyclist 2017-3-11

在 MATLAB Online 中打开

Here is one way.

val(:,:,1) = [
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0    22     0     0     1
     0     0     0     0     0
    33     0    -1     0     0
     0     0     0    -1     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0];
   val(:,:,2) = [
       0     0     0     0     0
      14     0     0     0     0
       0     0     4     0     0
       0     0     0     0     1
       0     0     0     0     0
       0     0     0     0     0
       0     0     0     0     0
       0    16     0     0     0
       0     0     0     2     0
       0     0     0     0     0];
newval = zeros(size(val));
newval(6,:,:) = reshape(val(val~=0),size(val(1,:,:)));

I made up some 3D data based on your first "slice". Then, I create a newval matrix that is the same size (but all zeros), and fill in the 6th row with the non-zero values from val.