subset data in sas using macro properly and append them to a file

Question

I have some data sets that I wrote some code to clean according to some methods according to some biological literature and then I want to split it into day and night (because they must be analyzed separately). It worked but now I need to do this for the full set which is WAY to many files for me to want to deal with one by one. So I am now trying to write a macro to split it into days and nights for me..

My data looks like so

   Hour         var1      var2      var3
     1            123       90       100
     2            122       99       108
     ...........
     4            156       80       120
     4            156       80       145
     4            143       82       132

basically night has 1 obs per hour day 3. I also have this for many days.

Each dataset is named STUDYIDID#_first or STUDYID_ID#_last. I want to generate four datasets per dataset. So MYID111_first would create: MYID111_first_day_var1, MYID111_first_day_var2, MYID111_first_night_var1 , and MYID111_first_night_var2.

I would then LIKE to append them into 4 datasets: MYID_A_first_day_var1, MYID_A_first_day_var2, MYID_A_first_night_var1 , and MYID_A_first_night_var2.

MY CODE SO FAR:

   %macro datacut(libname,worklib=work, grp = _A ,time1 = _night , time2 = _day type1 = _var1 , type2 = _var2);


   %local num i;
      proc datasets library=&libname memtype=data nodetails;
      contents out=&worklib..temp1(keep=memname) data=_all_ noprint;
    run;

   data _null_;
      set &worklib..temp1 end=final;
      by memname notsorted;
      if last.memname;
      n+1;
      call symput('ds'||left(put(n,8.)),trim(memname));

      if final then call symput('num',put(n,8.));

   run;

   %do i=1 %to #

   /* do the artifact removing method */
   DATA &libname..&&ds&i; 
   SET &libname..&&ds&i; 
       PT_ID = '&ds&i' ;
       IF var1< 60 OR var1> 230 then delete; 
       IF var2< 30 OR var2> 230 THEN delete; 
       IF var3< 60OR var3 > 135 THEN DELETE; 
       IF var2 > var1 then delete; 
   run;
   /* get just the night values */
   PROC SQL;
    CREATE TABLE &libname..&&ds&i&time1 as
        SELECT * 
        FROM &libname..&&ds&i 
        WHERE Hour BETWEEN 0 and 6 OR Hour BETWEEN 22 and 24
        order by systolic
    ; 
    QUIT;
    /* trim off the proper number of observations for variable 1 */
    DATA &libname..&&ds&i&time1&type1; 
    SET &libname..&&ds&i&time1  end=eof; 
        IF _N_ =1 then delete;  
        if eof then delete; 
    run;
   PROC append base= &libname..&&ds&time1&type1 
   data= &libname..&&ds&i&time1;
   run;

QUIT;


   %end;
%mend datacut;


%datacut(work)

Now the initial datastep works correctly but the later ones don't rename the data as planned. I get a bunch of datasets called Ds10_night_var1 with the wrong field names (memtype, nodetails, data)

I get the warning:

WARNING: Apparent symbolic reference DS1_NIGHT not resolved.
NOTE: Line generated by the macro variable "TIME1".
1      work.&ds1_night
            -
            22
            200
ERROR 22-322: Expecting a name.

ERROR 200-322: The symbol is not recognized and will be ignored.

NOTE: The SAS System stopped processing this step because of errors.
NOTE: PROCEDURE SQL used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds

WARNING: Apparent symbolic reference DS1_NIGHT_SYS not resolved.


22: LINE and COLUMN cannot be determined.
NOTE 242-205: NOSPOOL is on. Rerunning with OPTION SPOOL might allow recovery of the LINE and
              COLUMN where the error has occurred.
ERROR 22-322: Syntax error, expecting one of the following: a name, a quoted string, /, ;,
              _DATA_, _LAST_, _NULL_.
201: LINE and COLUMN cannot be determined.
NOTE: NOSPOOL is on. Rerunning with OPTION SPOOL might allow recovery of the LINE and COLUMN
      where the error has occurred.
ERROR 201-322: The option is not recognized and will be ignored.

So I want the right names for my file AND my datasets to actually have data I and I don't understand why they don't.

Answer 1

As you know, you write a macro variable as & followed by its name, optionally followed by .. With this . you can explicitly end the macro variable reference, so you can use a macro variable as a prefix, like in

%let prefix = fore;
Aspect = &prefix.Ground;

which evaluates to Aspect = foreGround;. And that is why

%let myLib = abc;
%let mymember = xyz;
data &myLib.&myMember;

is an error, as it evaluates to data abcxyz;, and you must write

data &myLib..&myMember; 
** or as I prefer **;
data &myLib..&myMember.;

to get data abc.xyz;.

For the case you need macro variables to create macro variable names from, SAS allows to write double ampersands &&, which evaluate to a single & and continues evaluating until all ampersands are consumed. So suppose

%let i = 1;
%let ds1 = myData;
%let time = _nigth;

This is how SAS evaluates &&ds&i&time1 :

• &&ds&i&time1
• &ds1_night
• ERROR because a macro variable ds1_night is not defined

This is how SAS evaluates &&ds&i..&time1. :

• &&ds&i..&time1.
• &ds1._night
• myData_night