# Creating two vectors from one.

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Giuseppe on 26 Mar 2014
Commented: Giuseppe on 26 Mar 2014
Hi I have a vector;
x = [2 4;3 -8; 1 2; 2 4;]
I need to produce two vectors like the ones to the left and right below. To get the vector on the right it is x_r = [2*-8 3*2 1*4] and same process for left(x_l) the arrows show what needs to be multiplied by what. If the number of rows (columns will always = two) increase or decrease or the numbers change I need to account for this. Is there a way where I can do this by vectorization or will I be stuck with loops.
Thanks,

Mischa Kim on 26 Mar 2014
Edited: Mischa Kim on 26 Mar 2014
Giuseppe, use
xr = x(1:end-1,1).*x(2:end,2)
xr =
-16
6
4
and equivalent for the other calculation.
Giuseppe on 26 Mar 2014
Thank you Mischa. You are a legend!

Chandrasekhar on 26 Mar 2014
x = [2 4;3 -8; 1 2; 2 4];
[m,n]=size(x);
for i= 1:m-1
a(i,1) = x(i,2)*x(i+1,1);
a(i,2) = x(i,1)*x(i+1,2);
end
Giuseppe on 26 Mar 2014
Thanks for the contribution. I really appreciate it.