SPSS® 12.0 Command Syntax Reference

Example
POINT 1221
an infinite loop in which the same record is read again and again, either the value of the
variable specified on KEY must change from case to case or the POINT command must be
set up to execute only once.
• If the file contains a record whose key exactly matches the value of the KEY variable, the
next execution of DATA LIST will read that record, the second execution of DATA LIST will
read the next record, and so on.
• If an exact match is not found, the results depend on the operating system. On IBM implementations,
reading will begin or resume at the record that has the next higher key. If the
value of the key is shorter than the file key, the value of the key variable is logically
extended with the lowest character in the collating sequence. For example, if the value of
the key variable is the single letter M, retrieval would begin or resume at the first record
that had a key (regardless of length) beginning with the letter M or a character higher in
the collating sequence.
• POINT does not report on whether the file contains a record that exactly matches the specified
key. The only way to check for missing records is to display the data read by the subsequent
DATA LIST command using LIST.
* Select a subset of records from a keyed file.
FILE HANDLE
INPUT PROGRAM.
DRIVERS/ file specifications.
STRING #FRSTAGE(A2).
DO IF #FRSTAGE = ’ ’. /* First case check
+ COMPUTE #FRSTAGE = ’26’. /* Initial key
+ POINT FILE=DRIVERS /KEY=#FRSTAGE.
END IF.
DATA LIST FILE=DRIVERS NOTABLE/
AGE 19-20(A) SEX 21(A) TICKETS 12-13.
DO IF
+ END FILE.
END IF.
AGE > ’30’.
END INPUT PROGRAM.
LIST.
• This example illustrates how to execute POINT for only the first case. The file contains
information about traffic violations, and it uses the individual’s age as the key. Ages
between 26 and 30 are selected.
• FILE HANDLE specifies the file handle DRIVERS.
• The INPUT PROGRAM and END INPUT PROGRAM commands begin and end the block of
commands that build cases. POINT must appear in an input program.
• STRING declares the string variable #FRSTAGE, whose value will be used as the key on
the POINT command. Since #FRSTAGE is a string variable, it is initialized as blanks.
• The first DO IF—END IF structure is executed only if no records have been read; that is,
when #FRSTAGE is blank. When #FRSTAGE is blank, COMPUTE resets #FRSTAGE to 26,
which is the initial value. POINT is executed, and it causes the first execution of DATA LIST
to read a record whose key is at least 26. Since the value of #FRSTAGE is now 26, the DO
IF—END IF structure is not executed again.