SAS 9.4 Macro Language, 5th Edition

Example 8: Dynamically Determine the Number of

Observations and Variables in a SAS Data Set

Details

This macro uses the functions OPEN and ATTRN to retrieve the total number of

observations and variables contained within a SAS data set.

Program

data test;

input a b c $ d $;

datalines;

1 2 A B

3 4 C D

;

%macro obsnvars(ds);

%global dset nvars nobs;

%let dset=&ds;

%let dsid = %sysfunc(open(&dset));

%if &dsid %then %do;

%let nobs =%sysfunc(attrn(&dsid,nlobs));

%let nvars=%sysfunc(attrn(&dsid,nvars));

%let rc = %sysfunc(close(&dsid));

%end;

%else %put open for data set &dset failed - %sysfunc(sysmsg());

%mend obsnvars;

%obsnvars(test)

%put &dset has &nvars variable(s) and &nobs observation(s).;

Program Description

Create a data set named Test.

data test;

input a b c $ d $;

datalines;

1 2 A B

3 4 C D

;

Begin the macro definition with one parameter.

%macro obsnvars(ds);

460 Appendix 5 • SAS Macro Examples

Create a global macro variable &DSET from the macro parameter &DS by using

%GLOBAL and %LET statements.

%global dset nvars nobs;

%let dset=&ds;

Use the OPEN function to open the data set that is passed to the macro.

%let dsid = %sysfunc(open(&dset));

Use the %IF statement to make sure the data set was open. If it is open, then run three

%LET statements.

• The first %LET statement creates a macro variable named &NOBS. The ATTRN

function is used with the NLOBS argument to retrieve the logical number of

observations in the data set.

• The second %LET statement creates a macro variable named &NVARS. The

ATTRN function is used along with the NVARS argument to retrieve the number of

variables in the data set.

• The third %LET statement uses the CLOSE function to close the data set that is

passed to the macro.

&DSID is the identifier that is returned from the OPEN function.

%if &dsid %then %do;

%let nobs =%sysfunc(attrn(&dsid,nlobs));

%let nvars=%sysfunc(attrn(&dsid,nvars));

%let rc = %sysfunc(close(&dsid));

%end;

If the %IF condition is false, meaning that the data set is not open, then use the %PUT

statement to write a statement to the log.

%else %put open for data set &dset failed - %sysfunc(sysmsg());

Close the macro definition.

%mend obsnvars;

Invoke the macro by passing in the data set name as a parameter.

%obsnvars(test)

Use the %PUT statement to write the information returned from the macro to the log.

%put &dset has &nvars variable(s) and &nobs observation(s).;

Example 8: Dynamically Determine the Number of Observations and Variables in a SAS

Data Set 461