MATLAB: How to extract labeled rows of a matrix

extraxtextraxt labeled rows from a matrixfor loopindexindexinglabeledmatrixrowssort

Hello Friends,
I have a matrix X of size NxD, where the Dth column is labeled. For example:
X = [1, 2, 3, Sunday
     4, 5, 6, Monday
     7, 8, 9, Sunday
     10, 11, 12, Tuesday
     13, 14, 15, Monday];
I want to extract the rows corresponding to each labels. So for above matrix, I should get the following matrices:
A = [ 1, 2, 3, Sunday
      7, 8, 9, Sunday];
    B = [4, 5, 6, Monday
         13, 14, 15, Monday];
    C = [10, 11, 12, Tuesday];
Here matrix A is of size 2xD, B is of size 2xD and C is of size 1xD.
I will appreciate any advise!

Best Answer

See if this does what you want:
X = {1, 2, 3, 'Sunday'
     4, 5, 6, 'Monday'
     7, 8, 9, 'Sunday'
     10, 11, 12, 'Tuesday'
     13, 14, 15, 'Monday'};
[UX,ia,ic] = unique(X(:,end), 'stable');
for k1 = 1:size(UX,1)
    Out{k1} = X(k1==ic,:);
end
Out{1}
Out{2}
Out{3}
ans = 
    [1.0000e+000]    [2.0000e+000]    [3.0000e+000]    'Sunday'
    [7.0000e+000]    [8.0000e+000]    [9.0000e+000]    'Sunday'
ans = 
    [ 4.0000e+000]    [ 5.0000e+000]    [ 6.0000e+000]    'Monday'
    [13.0000e+000]    [14.0000e+000]    [15.0000e+000]    'Monday'
ans = 
    [10.0000e+000]    [11.0000e+000]    [12.0000e+000]    'Tuesday'
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