Thread Subject:

How to split the matrix evenly spaced rows

I have matrix(A) with 12x4 like this:
A =
    1.7639 0.9502 0.7639 0.9172
    2.7984 0.7894 0.9357 0.7727
    3.9357 0.7727 0.7593 0.7581
    4.9344 0.7593 0.7455 0.9357
    5.7639 0.9502 0.7639 0.9172
    6.7984 0.7894 0.9357 0.7727
    7.9357 0.7727 0.7593 0.7581
    8.9344 0.7593 0.7455 0.9357
    9.7639 0.9502 0.7639 0.9172
   10.7984 0.7894 0.9357 0.7727
   11.9357 0.7727 0.7593 0.7581
   12.9344 0.7593 0.7455 0.9357

And I want to split it to matrix B like this:

B =
    1.7639 0.9502 0.7639 0.9172
    4.9344 0.7593 0.7455 0.9357
    7.9357 0.7727 0.7593 0.7581
    10.7984 0.7894 0.9357 0.7727

Could anyone help me please?
  

"Sum Nguyen" <sumkrongpac@yahoo.com> wrote in message <k0lobe$pb3$1@newscl01ah.mathworks.com>...
> I have matrix(A) with 12x4 like this:
> A =
> 1.7639 0.9502 0.7639 0.9172
> 2.7984 0.7894 0.9357 0.7727
> 3.9357 0.7727 0.7593 0.7581
> 4.9344 0.7593 0.7455 0.9357
> 5.7639 0.9502 0.7639 0.9172
> 6.7984 0.7894 0.9357 0.7727
> 7.9357 0.7727 0.7593 0.7581
> 8.9344 0.7593 0.7455 0.9357
> 9.7639 0.9502 0.7639 0.9172
> 10.7984 0.7894 0.9357 0.7727
> 11.9357 0.7727 0.7593 0.7581
> 12.9344 0.7593 0.7455 0.9357
>
> And I want to split it to matrix B like this:
>
> B =
> 1.7639 0.9502 0.7639 0.9172
> 4.9344 0.7593 0.7455 0.9357
> 7.9357 0.7727 0.7593 0.7581
> 10.7984 0.7894 0.9357 0.7727
>
> Could anyone help me please?
>
----------------------------X------------------------
This is pretty easy, using a loop.

If you want to extract every 3 rows from A and put them into B, then:

n=3; %interval between required rows
for ii = 1:n
     B = A(1:n:end,:);
end
----------------------------X------------------------

PS: I am sure that this can be done without a loop......using 1 or 2 lines of code. Just wait and see if someone else posts this.

"Stan" wrote in message <k0lqoa$5jo$1@newscl01ah.mathworks.com>...

>
> n=3; %interval between required rows
> for ii = 1:n
> B = A(1:n:end,:);
> end
> ----------------------------X------------------------

Why the loop is needed at all???

Bruno

"Stan" wrote in message <k0lqoa$5jo$1@newscl01ah.mathworks.com>...

> If you want to extract every 3 rows from A and put them into B, then:
>
> n=3; %interval between required rows
> for ii = 1:n
> B = A(1:n:end,:);
> end
> ----------------------------X------------------------

Actually, the loop I posted is not required. Here is the code that you need:

n=3;
B = A(1:n:end,:);

Sorry for the confusion.

"Sum Nguyen" <sumkrongpac@yahoo.com> wrote in message <k0lobe$pb3$1@newscl01ah.mathworks.com>...
> I have matrix(A) with 12x4 like this:
> A =
> 1.7639 0.9502 0.7639 0.9172
> 2.7984 0.7894 0.9357 0.7727
> 3.9357 0.7727 0.7593 0.7581
> 4.9344 0.7593 0.7455 0.9357
> 5.7639 0.9502 0.7639 0.9172
> 6.7984 0.7894 0.9357 0.7727
> 7.9357 0.7727 0.7593 0.7581
> 8.9344 0.7593 0.7455 0.9357
> 9.7639 0.9502 0.7639 0.9172
> 10.7984 0.7894 0.9357 0.7727
> 11.9357 0.7727 0.7593 0.7581
> 12.9344 0.7593 0.7455 0.9357
>
> And I want to split it to matrix B like this:
>
> B =
> 1.7639 0.9502 0.7639 0.9172
> 4.9344 0.7593 0.7455 0.9357
> 7.9357 0.7727 0.7593 0.7581
> 10.7984 0.7894 0.9357 0.7727
>
> Could anyone help me please?
>

Thanks everybody for the answer!