Specifying a New Variable in an ATTRIB Statement

The ATTRIB statement enables you to specify one or more of the following variable

attributes for an existing variable:

• FORMAT=

• INFORMAT=

• LABEL=

• LENGTH=

If the variable does not already exist, one or more of the FORMAT=, INFORMAT=, and

LENGTH= attributes can be used to create a new variable. For example, the following

DATA step creates a variable named FLAVOR in a data set named Lollipops:

data lollipops;

Flavor="Cherry";

attrib Flavor format=$10.;

run;

Note: You cannot create a new variable by using a LABEL statement or the ATTRIB

statement's LABEL= attribute by itself. Labels can be applied only to existing

variables.

For more information, see “ATTRIB Statement” in SAS Statements: Reference.

Using the IN= Data Set Option

The IN= data set option creates a special Boolean variable that indicates whether the

data set contributed data to the current observation. The variable has a value of 1 when

true, and a value of 0 when false. You can use IN= on the SET, MERGE, and UPDATE

statements in a DATA step.

The following example shows a merge of the Old and New data sets where the IN=

option is used to create a variable named X that indicates whether the New data set

contributed data to the observation:

data master missing;

merge old new(in=x);

by id;

if x=0 then output missing;

else output master;

run;

Variable Type Conversions

If you define a numeric variable and assign the result of a character expression to it, SAS

tries to convert the character result of the expression to a numeric value and to execute

the statement. If the conversion is not possible, SAS prints a note to the log, assigns the

numeric variable a value of missing, and sets the automatic variable _ERROR_ to 1. For

a listing of the rules by which SAS automatically converts character variables to numeric

variables and vice versa, see “Automatic Numeric-Character Conversion” on page 98.

44 Chapter 4 • SAS Variables

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Table of Contents for Specifying a New Variable in an ATTRIB Statement