The DROPEVENT statement specifies that some event variables
be excluded from the OUTEVENT= data set.
As a result, the DROPEVENT statement
is valid only for data files containing
event-oriented time series data, that is, only for CRSP files.
All the BY variables, the time ID variable DATE, and
the event-grouping variable EVENT are always
included in the OUTEVENT= data set.
These variables cannot be referenced in the DROPEVENT statement.
If any of these variables are referenced, a warning message is
given and the reference is ignored.
- DROPEVENT variable-list;
The variable list can contain variable names
or name range specifications.
See the section "Variable Lists" for details.
Only one DROPEVENT or one KEEPEVENT statement can be used.
DROPEVENT and KEEPEVENT are mutually exclusive.
You can also use the DROP= data set option
to control which event variables to exclude from
the OUTEVENT= data set. However, the DROPEVENT
statement differs from the DROP= data set option
in several aspects:
- The DROPEVENT statement selection is applied
before variables are read from the data file,
while the DROP= data set option selection is applied
after variables are read and as they are written to the OUTEVENT= data set.
Therefore, using the DROPEVENT statement instead of the DROP= data set option
is much more efficient.
- If the DROPEVENT statement causes all series variables to be excluded,
then no observations are output to the OUTEVENT= data set.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.