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Assign Matrix Name via DO Loop Function

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Contributor
Posts: 33

Assign Matrix Name via DO Loop Function

Hi! It's me again....

While working with the DO loop function I encountered another problemSmiley Wink I'd like to create several matrices with the help of the DO loop function but I'm still struggling with the matrices' names. Is it possible to assign a matrix name via the DO loop function as well?

Example:

do i=1 to 10;

Matrix_i=.....

end;

Thank you for your help!

Contributor
Posts: 33

Re: Assign Matrix Name via DO Loop Function

Oh... nevermind. I just discovered the article of Rick on this topic..... Thank you RickSmiley Wink

But maybe somebody knows how to address a specific matrix with the DO Loop Function.

Example:

the functions are as follows:

m1=x1

m2=x2-x1

...

m10=x10-x9

Thank you....

SAS Super FREQ
Posts: 3,415

Re: Assign Matrix Name via DO Loop Function

It is very rare that you need to have matrices of different names (as I explain in the article prior to the one you reference).

Sometimes people THINK they need to do this because they are trying to wrap SAS/IML statements within a macro loop, which is rarely necessary. Instead, you can use the SAS/IML language itself  to perform whatever the macro loop is doing.

You didn't post an example, but one common programming technique is to have all of the x vars in an nx10 matrix, where each column is a variable.

Then the following statements form a matrix m where each column is what you want:

y = j(n,1,0) || x; /* temp: append column of zeros */

m = y[,2:11] - y[,1:10];

free y;

Another alternative, if you don't need the whole matrix, is to loop:

do i = 1 to 10;

   if i = 1 then m=x[,i];

   else m = x[,i] - x[,i-1];

   /* do something with m, which is m_i in your notation */

end;

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