-1 and 1 matrix

Hello All,

 I want to create a  n X n matrix with 1row 1, 2nd row -1, 3rd row 1 , 4th row -1 and so on..... can anyone please guide me .......... thanks.........

Answer 1

[Stephen23]

Method One:

>> N = 5;
>> 2*mod(ndgrid(1:N,1:N),2)-1
ans =
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1

Method Two:

>> 2*(ones(N,1)*mod(1:N,2)).'-1
ans =
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1

Method Three:

>> repmat(2*mod(1:N,2).'-1,1,N)
ans =
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1
  -1    -1    -1    -1    -1
   1     1     1     1     1

Answer 2

[Andrei Bobrov]

-(-1).^(1:5)'*ones(1,5);

[Stephen23]

Very nice!

[Offroad Jeep]

Thanks.........

[Andrei Bobrov]

 please accept my answer too! :)