INDEX= Data Set Option
Defines an index for a new output SAS data set.
| Valid in: |
DATA step and PROC steps |
| Category: |
Data Set Control |
| Restriction: |
Use with output data sets only. |
Syntax
INDEX=(index-specification-1 ...<index-specification-n> )
Syntax Description
- index-specification
-
names and describes
a simple or a composite index to be built.
Index-specification has this form:
index= (variable(s) </UNIQUE> </NOMISS> )
- index
-
is the name of a variable
that forms the index or the name that you choose for a composite index.
- variable or variables
-
is a list of variables
to use in making a composite index.
- UNIQUE
-
specifies that the
values of the key variables must be unique. If you specify UNIQUE
for a new data set and multiple observations have the same values
for the index variables, the index is not created. A slash (/) must
precede the UNIQUE option.
- NOMISS
-
excludes all observations
with missing values from the index. Observations with missing values
are still read from the data set but not through the index. A slash
(/) must precede the NOMISS option.
Examples
Example 1: Defining a Simple Index
The following INDEX=
data set option defines a simple index for the SSN variable:
data new(index=(ssn));
Example 2: Defining a Composite Index
The following INDEX=
data set option defines a composite index named CITYST that uses the
CITY and STATE variables:
data new(index=(cityst=(city state)));
Example 3: Defining a Simple and a Composite Index
The following INDEX=
data set option defines a simple index for SSN and a composite index
for CITY and STATE:
data new(index=(ssn cityst=(city state)));
Example 4: Defining a Simple Index with the UNIQUE Option
The following INDEX=
data set option defines a simple index for the SSN variable with unique
values:
data new(index=(ssn /unique));
Example 5: Defining a Simple Index with the NOMISS Option
The following INDEX=
data set option defines a simple index for the SSN variable, excluding
all observations with missing values from the index:
data new(index=(ssn /nomiss));
Example 6: Defining Multiple Indexes Using the UNIQUE and NOMISS Options
The following INDEX=
data set option defines a simple index for the SSN variable and a
composite index for CITY and STATE. Each variable must have a UNIQUE
and NOMISS option:
data new(index=(ssn /unique/nomiss cityst=(city state)/unique/nomiss));