how to discard NaN vectors from a 3D matrix

Hi, I have a 3D matrix. some of its rows/columns/depth vectors can be all NaN. I wish to creat a new matrix which is the same as the original one only without the NaNs. is there a function that can help me do this ? in 2D i used ismember and just substitute them with []. but for the 3D case im stuck. here is an example code of such matrix

mat=ones(6,6,6);
mat(1:2,:,:)=NaN(2,6,6);
NANLoc=isnan(mat);

( so I want mat(3:6,:,:) as a new matrix)

any ideas? thanks

Answer 1

[ag]

Hi Itzik,

I understand that you are want to remove all slices in your 3D matrix that contain NaN values. You can achieve this by utilizing the "isnan" function in MATLAB.

Below is a code snippet that demonstrates how to accomplish this:

% Identify slices to keep (those without any NaN values)
slicesToKeep = ~any(any(isnan(M), 1), 2);

% Construct the new matrix by retaining only the non-NaN slices
newM = M(:, :, slicesToKeep);

For more details, please refer to the following MathWorks documentation:

• isnan - https://www.mathworks.com/help/matlab/ref/double.isnan.html
• any - https://www.mathworks.com/help/matlab/ref/any.html

Hope this helps!