CODEWITHSUNDEEP
arraysmatlabmultidimensional-array
Windy Day
Windy Day

Reputation: 173

How to insert a blank array in a multidimensional array in MATLAB?

I have a 3D matrix 't' of size 174x162x286 representing longitude x latitude x timestep. However, there are three timesteps missing in 't'. I need to insert a blank array at these specific places such that the end product will be 't' of size 174x162x289.

t(:,:,236)=NaN;

I do not want to shift the entire array.

Upvotes: 0

Views: 55

Answers (1)

Luis Mendo
Luis Mendo

Reputation: 112659

You can do it in one go as follows:

t = randi(9, 2, 4, 7); % example data
ind_insert = [3 5 6 6]; % insert immediately after these 3rd-dim positions 

[~, ind] = sort([1:size(t,3) ind_insert]); % exploits the fact that sorting is stable
t = cat(3, t, NaN(size(t,1), size(t,2), numel(ind_insert)));
t = t(:,:,ind);

Example: before:

t(:,:,1) =
     3     7     4     7
     3     8     8     1
t(:,:,2) =
     6     9     5     5
     4     1     4     7
t(:,:,3) =
     3     5     2     5
     8     1     7     2
t(:,:,4) =
     4     2     3     3
     6     7     9     7
t(:,:,5) =
     2     1     7     4
     3     6     5     6
t(:,:,6) =
     6     6     2     3
     7     9     7     2
t(:,:,7) =
     6     5     7     6
     5     6     4     4

After:

t(:,:,1) =
     3     7     4     7
     3     8     8     1
t(:,:,2) =
     6     9     5     5
     4     1     4     7
t(:,:,3) =
     3     5     2     5
     8     1     7     2
t(:,:,4) =
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
t(:,:,5) =
     4     2     3     3
     6     7     9     7
t(:,:,6) =
     2     1     7     4
     3     6     5     6
t(:,:,7) =
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
t(:,:,8) =
     6     6     2     3
     7     9     7     2
t(:,:,9) =
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
t(:,:,10) =
   NaN   NaN   NaN   NaN
   NaN   NaN   NaN   NaN
t(:,:,11) =
     6     5     7     6
     5     6     4     4

Upvotes: 3

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