topic Re: SAS arrays in SAS Programming

SAS arrays

Acp — Sat, 18 Feb 2017 12:48:32 GMT

array salv(*) Performance_:;                                                                                                            
array delqnorm(26);                                                                                                                     
array maxdelqnorm(26);                                                                                                                  
format maxdelqfirst12m maxdelqever 1.;                                                                                                  
do i = 1 to 26;                                                                                                                         
  if not missing (delq(i)) then                                                                                                         
    do;                                                                                                                                 
      offset=i;                                                                                                                         
          i=26;                                                                                                                         
    end;                                                                                                                                
end;

Hi im new to sas programming... I'd came out through this code on SAS arrays... can anybody explain me what does "Performance_:" in line 1st and "offset=i" is representing here?

Re: SAS arrays

mkeintz — Sat, 18 Feb 2017 13:16:48 GMT

There are many ways to generate lists of variables names for use in array, keep, drop and other statements.

The use of the right hand colon says to use all vars whose name begins with "performance_".

You could also use

array x{*} performance_1-performance_5; /* single dash,which tells sas to look generate all vars performanc_1 performance_2 performance_3 performance_4 performance_5.*/

or a specific list:

array x{*} performance_1 performance_2 performance_2 performance_4 performance_5;

or a double dash

array x{*} perform -- return ; /* which says to use all vars from perform through return in the program data vector.*/

Re: SAS arrays

Acp — Sat, 18 Feb 2017 13:19:08 GMT

Thanks man for providing such an easy solution.... and can you please tell what would be the use of "offset" in above program?

Re: SAS arrays

mkeintz — Sat, 18 Feb 2017 13:25:37 GMT

The expression DELQ{i} says to use the i'th element of the array named DELQ, where i ranges from 1 to 26 in the DO loop (so your array better have at least 26 elements). These 26 values are examined, and OFFSET will end up as the index of the "most recent" (i.e. the rightmost) element of the DELQ array that is non-missing.

Re: SAS arrays

Shmuel — Sat, 18 Feb 2017 15:40:33 GMT

Just to add to @mkeintz post, you have a sysntax error in your code:

in order to use delq(i) you have to define array by:

array delq {26} delq_1 - delq_26; /* or delq: or xxx1-xxx26. See @mkeintz post */

- delq is the array name, while

- delq1-delq26 are the variables making the array

Beyond, what did you mean by line:

array maxdelqnorm(26);

are there 26 max values ? what variables create the array called maxdelqnorm?

Re: SAS arrays

Tom — Sat, 18 Feb 2017 21:54:24 GMT

The statement

offset=i;

Is just an assignment statement. So it sets the value of OFFSET to the current value of I.

The purspose seems to store the index into the array of the first non-missing element in the array. So the offset from the begginnig of the list.

So if you array had the series of values :

. . . . 15 23 7 .

Then OFFSET would get set to 5 since the first non-missing value is the 15 in the fifth position.

The statement

I=26;

Is intended to cause the DO loop to end.

You could re-write it like this and it might be a little clearer.

offset=.;
do i=1 to dim(delq) while (offset=.);
  if not missing(delq(i)) then offset=i;
end;

Also make sure the name you use in the ARRAY statement matches the name you are using in your array references. This loop is referencing the array named DELQ, but you did not include an ARRAY statement to define that array in the code you posted.