SAS Certification Prep Guide, 4th Edition

Using Conditional Clauses with the Iterative DO Statement

Previous examples showed that the DO WHILE and DO UNTIL statements enable you to execute statements conditionally and that the iterative DO statement enables you to execute statements a set number of times, unconditionally.

DO WHILE(expression); 
DO UNTIL(expression); 
DO index-variable=start TO stop BY increment;

In this DATA step, the DO UNTIL statement determines how many years it takes (13) for an investment to reach $50,000.

data work.invest; 
   do until(Capital>=50000);  
      Year+1; 
      capital+2000; 
      capital+capital*.10; 
   end; 
run;

Figure 15.5 SAS Data Set Work.Invest: Number of Years for an Investment to Reach $50,000

Suppose you also want to limit the number of years you invest your capital ...