| Generating Data with DO Loops |
| Constructing DO
Loops |
| Counting DO Loop Iterations
In some cases, it is more useful to create a variable to count and store the number of iterations in the DO loop. Then you can drop the index variable from the data set. |
data work.earn (drop=year);
Value=2000;
do year=1 to 20;
Interest=value*.075;
value+interest;
Years+1;
end;
run;
|
SAS Data Set Work.Earn
|
The sum statement accumulates the number of iterations of the DO loop
and stores the total in the variable Years. The final value of
Years is stored in the data set.
You can also include an OUTPUT statement within the DO loop to write an observation to the data set for each iteration of the DO loop. The OUTPUT statement writes the current values to the data set immediately. By including the OUTPUT statement, you override the automatic output at the end of the DATA step. When the index variable is 21, the observation is not written to the data set. |
data work.earn;
Value=2000;
do year=1 to 20;
Interest=value*.075;
value+interest;
output;
end;
run;
|
Partial Listing of SAS Data Set Work.Earn
|
| During each iteration of the DO loop, an observation is written to the Work.Earn data set. |
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Copyright © 2002 SAS Institute Inc.,
Cary, NC, USA. All rights reserved.