FILTER BY var_name. FILTER OFF.
FILTER allows a boolean-valued variable to be used to select
cases from the data stream for processing.
To set up filtering, specify BY and a variable name. Keyword
BY is optional but recommended. Cases which have a zero or system- or
user-missing value are excluded from analysis, but not deleted from the
data stream. Cases with other values are analyzed.
To filter based on a different condition, use
transformations such as COMPUTE or RECODE to compute a
filter variable of the required form, then specify that variable on
FILTER.
FILTER OFF turns off case filtering.
Filtering takes place immediately before cases pass to a procedure for
analysis. Only one filter variable may be active at a time. Normally,
case filtering continues until it is explicitly turned off with FILTER
OFF. However, if FILTER is placed after TEMPORARY, it filters only
the next procedure or procedure-like command.