RUN-group processing in SAS/Graph procedures

In SAS packages, some procedures may support RUN-group processing, e.g. Proc CATALOG, Proc DATASETS in SAS/Base, Proc GPLOT, Proc GCHART in SAS/Graph and Proc REG in SAS/STAT, etc.

Basically, RUN-group processing is used to perform task interactivly and efficiently without restarting the procedure. It is very intersting that ONLY the ones in SAS/Graph can reset or cancel global and local statements, BY statements, WHERE statement.

* Sample Code;
proc sort data=sashelp.class out=class;
 by name;
run;
proc gplot data=class;
 where;
 by;
 title "All Subjects";
 plot height*weight;
run;
 where sex='M';
 by name;
 title "Male";
 plot height*weight;
run;
 where sex='F';
 by;
 title "Female";
 plot height*weight;
run;
quit;

For more information, please read SAS/GRAPH Processing: RUN-Group Processing.

Read and sort in one step - Hash object tip

In SAS world, the classical way to process raw file is to read it into SAS dataset and then sort it. With SAS9 Hash object in DATA step, we can make an all-in-one step.

* Hash sample - read and sort raw data;
data _null_;   
   /* Declare hash object and key and data variable names */
   if _N_ = 1 then do;
      declare hash h(ordered:'A');
      rc = h.defineKey('key');
      rc = h.defineData('key','value');
      rc = h.defineDone();
   end;

   /* Read key and data values */
   infile datalines eof=eof;
   input key value $;

   /* Add key and data values to hash object */
   rc = h.add();

   return;
   eof: rc = h.output(dataset:"ordered");
cards;
1 value1
3 value2
2 value3
;

Actually, it is only one little tip of Hash object.
We must never forget that the main functionality of Hash object is to quickly and efficiently store, search, and retrieve data based on lookup keys.

To list ALL using PRELOADFMT

The option PRELOADFMT is available only with Proc MEANS, Proc REPORT and Proc TABULATE.
To include all ranges and values of the user-defined formats in the output, the 3 Procs give out different usages.
Below are the samples for that.

proc format;
value $sex
    'M' = 'Male' 'F' = 'Female' 'O' = 'Other';
run;

proc means data=sashelp.class completetypes mean;
    format sex $sex.;
    class sex / preloadfmt;
    var height;
run;

proc report data=sashelp.class completerows nowd;
    format sex $sex.;
    column sex height;
    define sex / group preloadfmt;
    define height / analysis mean;
run;

proc tabulate data=sashelp.class ;
    format sex $sex.;
    class sex / preloadfmt;
    var height;
    tables sex*height*mean / printmiss;
run;

Logical expression play differently between %eval and DATA step

When programming macro, It is helpful to complete it in a DATA step and then port the code to macro. However, not all tricks in DATA step work in macro world.

Below is one tip for that:

data _null_;
    do a=1 to 4;
        if 1 < a < 3 then put a= "is between 1 and 3";
    end;
run;

%macro test();
    %put Wrong example:;
    %do a=1 %to 4;
        %if %eval(1 < &a < 3) %then 
            %put a=&a is between 1 and 3;
    %end;

    %put Correct example:;
    %do a=1 %to 4;
        %if %eval(1 < &a and &a < 3) %then 
            %put a=&a is between 1 and 3;
    %end;
%mend;

%test()

Get nth value of a variable

It is another idea to get nth value of a variable.

proc sort data=sashelp.class out=tmp(keep=weight) 
     nodupkey;
  by descending weight;
run;

data _null_;
  set tmp end=end;

  retain weight_10th .;
  if _n_ <= 10 then do;
    weight_10th = weight;
  end;

  if end then put "The 10th weight is " weight_10th=;
run;

undocumented routine: CALL SOUND

I always keep an eye closely on SAS Samples, where I can get many interesting tips.

From this new sample, we can infer that CALL SOUND is another undocumented routine.
It will be a great way for reminder, not just in EG.

CALL SORTx routines

With CALL SORTx routines, we can sort and EXCHANGE the values of the variables. It is a very helpful since we need not assign a temporary variable for exchange of the values.
Below is an interesting sample code:

* Get the first two max height values;
data _null_;
  set sashelp.class end=last;
  retain max1 max2;

  call sortn(height, max2, max1);
  if last then put "max height value: " max1 max2;
run;