SPSS® 12.0 Command Syntax Reference

740 IF
Example
Example
* Test for listwise deletion of missing values.
DATA LIST /V1 TO V6 1-6.
STRING SELECT(A1).
COMPUTE SELECT=’V’.
VECTOR V=V1 TO V6.
LOOP #I=1 TO 6.
IF MISSING(V(#I)) SELECT=’M’.
END LOOP.
BEGIN DATA
123456
56
1 3456
123456
123456
END DATA.
FREQUENCIES VAR=SELECT.
• STRING creates the string variable SELECT with an A1 format and COMPUTE sets the
value of SELECT to V.
• VECTOR defines the vector V as the original variables V1 to V6. Variables on a single
vector must be all numeric or all string variables. In this example, because the vector V is
used as an argument on the MISSING function of IF, the variables must be numeric
(MISSING is not available for string variables).
• The loop structure executes six times: once for each VECTOR element. If a value is
missing for any element, SELECT is set equal to M. In effect, if any case has a missing
value for any of the variables V1 to V6, SELECT is set to M.
• FREQUENCIES generates a frequency table for SELECT. The table gives a count of how
many cases have missing values for at least one variable and how many cases have valid
values for all variables. This table can be used to determine how many cases would be
dropped from an analysis that uses listwise deletion of missing values. See pp. 257 and
497 for alternative ways to test for listwise deletion of missing values.
IF YRHIRED LT 1980 RATE=0.02.
IF DEPT=’SALES’ DIVISION=’TRANSFERRED’.
• The logical expression on the first IF command tests whether YRHIRED is less than 1980
(hired before 1980). If so, the variable RATE is set to 0.02.
• The logical expression on the second IF command tests whether DEPT equals SALES.
When the condition is true, the value for the string variable DIVISION is changed to
TRANSFERRED but is truncated if the format for DIVISION is not at least 11 characters
wide. For any other value of DEPT, the value of DIVISION remains unchanged.
• Although there are two IF statements, each defines a separate and independent condition.
The IF command is used rather than the DO IF—END IF structure in order to test both condi-