KEEP= Data Set Option
For an input data set, specifies the columns to
process; for an output data set, specifies the columns to write to
the data set.
| Valid in: |
DATA and PROC steps |
| Category: |
Variable Control |
| Supports: |
All |
Syntax
Syntax Description
- column(s)
-
lists one or more column
names. You can list the columns in any form that SAS allows.
Details
When the KEEP= data
set option is associated with an input data set, only those columns
that are listed after the KEEP= data set option are available for
processing. When the KEEP= data set option is associated with an output
data set, only the columns listed after the option are written to
the output data set. However, all columns are available for processing.
Comparisons
-
The KEEP= data set option differs
from the KEEP statement in the following ways:
-
In DATA steps, the KEEP= data set
option can apply to both input and output data sets. The KEEP statement
applies only to output data sets.
-
In DATA steps, when you create
multiple output data sets, use the KEEP= data set option to write
different columns to different data sets. The KEEP statement applies
to all output data sets.
-
In PROC steps, you can use only
the KEEP= data set option, not the KEEP statement.
-
The DROP= data set option specifies
columns to omit during processing or to omit from the output data
set.
Example: Limit Columns in the SET Statement
In this example, only
IDNUM and SALARY are read from PAYROLL, and they are the only columns
in PAYROLL that are available for processing:
data myfiles.bonus;
set myfiles.payroll (keep=idnum salary);
bonus=salary*1.1;
run;
proc print data=myfiles.bonus(obs=2);
title 'bonus data set';
run;