PROC FORMAT
To change the appearance of the variable entries in our data set we can use a proc format step, there we can impose a new name on our entries A and B that describe the type of treatment.
Text format
is used if the variable entries are text, e.g. A and B. The difference to numeric formats is the $-sign.
proc format ;
value $treatmentnames
"A" = "Standard treatment"
"B" = "New treatment";
run;
Explanation:
The value statement defines a new format. Here the format is called treatmentnames. It includes two formats: A will be called 'Standard treatment' and B will be called 'New treatment'.
The format effects output only if it is called upon, e.g. if we make a table:
Without formats:
proc freq data=indata2;
table type*date /nocol norow nopercent;
run;
With formats:
proc freq data=indata2;
table type*date /nocol norow nopercent;
format type $treatmentnames.;
run;
Numeric format
is used if the variable entries are numerical. Assume we have a variable with entries 1-7 describing the day of week and we want to express this as text.
proc format library=formats;
value weekdayformat
1= 'Sunday'
2= 'Monday'
3='Tuesday'
4='Wednesday'
5='Thursday'
6='Friday'
7='Saturday'
run;
Further reading:
https://stats.idre.ucla.edu/sas/faq/how-can-i-change-the-way-variables-are-displayed-in-proc-freq/
PROC FORMAT: An Analyst’s Buddy : http://www2.sas.com/proceedings/sugi31/084-31.pdf
THE POWER OF PROC FORMAT:
https://stats.idre.ucla.edu/wp-content/uploads/2016/02/bt3001.pdf