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 that are 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: Limiting Columns in the SET Statement
In this example, only
columns 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;