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DO

Valid:	in a DATA step
Category:	Control
Type:	Executable

Without Arguments

Use the DO statement for simple DO group processing.

Details

The DO statement is the simplest form of DO group processing. The statements between the DO and END statements are called a DO group. You can nest DO statements within DO groups.

Note:   The memory capabilities of your system may limit the number of nested DO statements you can use. For details, see the SAS documentation about how many levels of nested DO statements your system's memory can support.   

A simple DO statement is often used within IF-THEN/ELSE statements to designate a group of statements to be executed depending on whether the IF condition is true or false.

Comparisons

There are three other forms of the DO statement:

• The iterative DO statement executes statements between DO and END statements repetitively based on the value of an index variable. The iterative DO statement can contain a WHILE or UNTIL clause.

• The DO UNTIL statement executes statements in a DO loop repetitively until a condition is true, checking the condition after each iteration of the DO loop.

• The DO WHILE statement executes statements in a DO loop repetitively while a condition is true, checking the condition before each iteration of the DO loop.

Examples

In this simple DO group, the statements between DO and END are performed only when YEARS is greater than 5. If YEARS is less than or equal to 5, statements in the DO group do not execute, and the program continues with the assignment statement that follows the ELSE statement.

if years>5 then
   do;
      months=years*12;
      put years= months=;
   end;
   else yrsleft=5-years;

Statements: DO, Iterative DO UNTIL DO WHILE

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