could anyone tell me how to group the combinations under the condition that the same number should not be repeated again.

code: c = combnk(1:4,2)

If i run it i am getting c =

     3     4
     2     4
     2     3
     1     4
     1     3
     1     2

could anyone help me how to group the numbers say for example (34,12),(24,13) and (23,14) in the following way.

Answer 1

[KSSV]

c = combnk(1:4,2) ;

   N = sum(c.*[10 1],2) ;

   iwant = [N(1:3) N(length(N):-1:4)]

[Prabha Kumaresan]

when i run it i am getting Error using .* Matrix dimensions must agree.

Error in line N = sum(c.*[10 1],2) ;could you help me to solve it.

[KSSV]

That case...I suspect you have changed C....try to understand the code...and then implement it.

[Prabha Kumaresan]

no i havent changed C.

c = combnk(1:4,2)
N = sum(c.*[10 1],2) 
iwant = [N(1:3) N(length(N):-1:4)]

when i run the code i am getting

c =

       3     4
       2     4
       2     3
       1     4
       1     3
       1     2

Error using  .* 
Matrix dimensions must agree.

Error in two (line 6)
   N = sum(c.*[10 1],2)

[Walter Roberson]

User is using a version older than R2016b so no implicit expansion

[Prabha Kumaresan]

i am using version of 2015b.

[Prabha Kumaresan]

what should be done in case of 2015b.

[Walter Roberson]

   N = c * [10;1];

Answer 2

[Rik]

The code below is the same as the code by KSSV, but without the need for implicit expansion.

c = combnk(1:4,2);
N = c * [10;1];
iwant = [N(1:3) N(length(N):-1:4)];

[Walter Roberson]

Except that you don't need bsxfun either ;-)

     N = c * [10;1];

[Rik]

Good point, I'll edit my answer. I guess taking a step back when looking at a problem never hurts.

[Prabha Kumaresan]

ok.But i want to group the numbers (3 4,1 2),(2 4,1 3) and (2 3,1 4) in this manner.I dont want to have command line. N = c * [10;1 ] as it does product and sum. I just want to group the numbers.

[Walter Roberson]

Your question ends with "in the following way." without an example of the output you want.