NULL Subcommand (VARSTOCASES command)
The NULL
subcommand
checks each potential new row for null values. A null value is a system-missing or blank value. By default, VARSTOCASES
does not add a new row that
contains null values for all variables created by MAKE
subcommands. You can change the default
null-value treatment with the NULL
subcommand.
DROP. Do not
include a new row when all MAKE variables are null. A
potential new row with null values for all of the variables created
by MAKE
subcommands is excluded
from the new data file. This is the default. With this option, you
may want to create a count variable to keep track of new rows because
cases in the original data file are not guaranteed to appear in the
new data file.
KEEP. Include a new
row when all MAKE variables are null. A potential new
row with null values for all of the variables created by the MAKE
subcommand is included in the new data.
With this option, you may not need a count variable to keep track
of cases because each row in the original data will result in a consistent
number of rows in the new data file.