Converting 2-d[:,45] matrix to 3-d[:,45,246] matrix based on unique values in 2nd column of 2d matrix

I have a 2-d matrix with [:, 45] dimension, which I want to convert into a 3-d matrix of dimension [:,45,246] based on 246 unique values on 2nd column of 2-d matrix.

[Walter Roberson]

Okay, but you have not been clear as to what goes into each pane of the new array.

[Mudasser Seraj]

what do you mean by pane? I don't know the first dimension of the matrix.

[Jan]

Please give a short example. It is impossible to guess, which operation you want.

Answer 1

[Walter Roberson]

[uniquevals, ~, idx] = unique(YourMatrix(:,2));
for J = 1 : length(YourMatrix,1)
  NewMatrix(J, :, idx(J)) = YourMatrix(J, :);
end