Loop to separate rows in one matrix and delete elements in that matrix based on another matrix

I want to write a for loop that will allow me to extract each row of a matrix and then remove elements from such rows based on elements in another matrix that meet a certain criteria. To explain this further, I have matrix b_loc, which is a 510x977 matrix and matrix z_probs which is a 510 x 977 x 2 matrix. For the first round of the loop I want to extract the first row of matrix b_loc then remove any values in that row that correspond to the positions z_probs(1,:,1)<0.5. For the second round of the loop I want to extract the second row of matrix b_loc then remove any values in that row that correspond to the positions z_probs(2,:,1)<0.5. And so on for all 510 rows. I have tried using the following code and I keep getting the error: Unable to perform assignment because brace indexing is not supported for variables of this type.

for i=1:510

b_aoi{i}=b_loc(i,:)

b_removed{i}=b_aoi{i}(z_probs(i,:,1)>0.5)

end

Any help would be greatly appreciated!

Answer 1

[Sindar]

% find indices where z_probs<0.5
idx = (z_probs(:,:,1)<0.5);
% "remove" those values in b_loc by setting them to NaN
b_loc(idx)=nan;

[AS]

Thanks. This sort of worked. I had to add in additional steps for the for loop. But the idea helped.