how to create group from matrix

hi, i want to do table group :

1 column :3,5,9,12

2 column: 4,6,7,8,10,11

3 colum (no..because this element are identical at colum 1 )

..

the column with all zero element to be not insert! (and the column egual )

finally i get this matrix (colum 5,6,7,8 are clone...i not insert it in the group)

1 column :3,5,9,12,0,0

2 column: 4,6,7,8,10,11

i try to use world reserved "unique" but i can't do it

Answer 1

[Voss]

M = [0 0 3 4 3 4 4 4; 0 0 5 6 5 6 6 6; 0 0 9 7 9 7 7 7; 0 0 12 8 12 8 8 8; 0 0 0 10 0 10 10 10; 0 0 0 11 0 11 11 11; 0 0 0 0 0 0 0 0; 0 0 0 0 0 0 0 0; 0 0 0 0 0 0 0 0]

M = 9×8

0 0 3 4 3 4 4 4 0 0 5 6 5 6 6 6 0 0 9 7 9 7 7 7 0 0 12 8 12 8 8 8 0 0 0 10 0 10 10 10 0 0 0 11 0 11 11 11 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

% unique() by column:
M = unique(M.','rows','stable').'

M = 9×3

0 3 4 0 5 6 0 9 7 0 12 8 0 0 10 0 0 11 0 0 0 0 0 0 0 0 0

% remove all-0 rows:
M(all(M == 0,2),:) = [];

% remove all-0 columns:
M(:,all(M == 0,1)) = [];

disp(M);

     3     4
     5     6
     9     7
    12     8
     0    10
     0    11

[pipin]

M = unique(M.','rows','stable').'

what is . after M? (M.)

i try to remove it and the result is the same

[Voss]

.' is transpose

https://www.mathworks.com/help/matlab/ref/transpose.html

' is complex conjugate transpose

https://www.mathworks.com/help/matlab/ref/ctranspose.html

By removing the . you went from using tranpose to complex conjugate transpose, which means that the code will not work as intended for complex-valued matrices. But since your matrix is real-valued its complex conjugate is itself so the result is the same whether you use .' or ' in this case.

[pipin]

thank you for explenation

[Voss]

You're welcome!