SPSS® 12.0 Command Syntax Reference

IF
IF [(]logical expression[)] target variable=expression
The following relational operators can be used in logical expressions:
Symbol Definition Symbol Definition
EQ or = Equal to NE or * Not equal to
LT or < Less than LE or Greater than GE or >= Greater than or equal to
* On ASCII systems (for example, UNIX, VAX, and all PC’s) you can also use ~=;
on IBM EBCDIC systems (for example, IBM 360 and IBM 370) you can also use ¬=.
The following logical operators can be used in logical expressions:
Symbol Definition
AND or & Both relations must be true
Or or | Either relation can be true
Not* Reverses the outcome of an expression *
* On ASCII systems you can also use ~; on IBM EBCDIC systems
you can also use ¬ (or the symbol above number 6).
Example
Overview
IF (AGE > 20 AND SEX = 1) GROUP=2.
IF conditionally executes a single transformation command based upon logical conditions
found in the data. The transformation can create a new variable or modify the values of an
existing variable for each case in the working data file. You can create or modify the values
of both numeric and string variables. If you create a new string variable, you must first declare
it on the STRING command.
IF has three components: a logical expression (see “Logical Expressions” on p. 48) that
sets up the logical criteria, a target variable (the one to be modified or created), and an
assignment expression. The target variable’s values are modified according to the assignment
expression.
IF is most efficient when used to execute a single, conditional, COMPUTE-like transformation.
If you need multiple IF statements to define the condition, it is usually more efficient
to use the RECODE command or a DO IF—END IF structure.
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