IFN Function

shiyiming

Returns a numeric value based on whether an expression is true, false, or missing.
Syntax
IFN(logical-expression, value-returned-when-true, value-returned-when-false <,value-returned-when-missing>)  


Arguments


logical-expression
specifies a numeric constant, variable, or expression.

value-returned-when-true
specifies a numeric constant, variable, or expression that is returned when the value of logical-expression is true.

value-returned-when-false
specifies a numeric constant, variable, or expression that is returned when the value of logical-expression is false.

value-returned-when-missing
specifies a numeric constant, variable or expression that is returned when the value of logical-expression is missing.


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Details


The IFN function uses conditional logic that enables you to select among several values based on the value of a logical expression.

IFN evaluates the first argument, then logical-expression. If logical-expression is true (that is, not zero and not missing), then IFN returns the value in the second argument. If logical-expression is a missing value, and you have a fourth argument, then IFN returns the value in the fourth argument. Otherwise, if logical-expression is false, IFN returns the value in the third argument.

The IFN function, an IF/THEN/ELSE construct, or a WHERE statement can produce the same results (see Examples). However, the IFN function is useful in DATA step expressions when it is not convenient or possible to use an IF/THEN/ELSE construct or a WHERE statement.


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Comparisons


The IFN function is similar to the IFC function, except that IFN returns a numeric value whereas IFC returns a character value.


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Examples




Example 1: Calculating Sales Commission
The following examples show how to calculate sales commission using the IFN function, an IF/THEN/ELSE construct, and a WHERE statement. In each of the examples, the commission that is calculated is the same.



Calculating Commission Using the IFN Function
In the following example, IFN evaluates the expression TotalSales > 10000 . If total sales exceeds $10,000, then the sales commission is 5% of the total sales. If total sales is less than $10,000, then the sales commission is 2% of the total sales.

data _null_;
   input TotalSales;
   commission=ifn(TotalSales > 10000, TotalSales*.05, TotalSales*.02);
   put commission=;
   datalines;
25000
10000
500
10300
;

run;

SAS writes the following output to the log:

commission=1250
commission=200
commission=10
commission=515