How to Determine if a variable exists in the dataset or not

Programatically determine if a variable exists in a data set

Use the OPEN and VARNUM functions to determine if a variable exists in a SAS data set. The OPEN function opens a SAS data set and returns a data set identifier. The VARNUM function returns the variable's position in the data set. If the variable does not exist then VARNUM returns a 0.

/* Create sample data */
data test;
input fruit $ count;
datalines;
apple 12
banana 4
coconut 5
date 7
eggs 9
fig 5
;
/* Specify the data set to open in the OPEN function. Specify the */
/* variable to be located in the second parameter of the VARNUM */
/* function. If the variable does not exist, the value of check */
/* will be zero. */

data _null_;
dsid=open('test');
check=varnum(dsid,'count');
if check=0 then put 'Variable does not exist';
else put 'Variable is located in column ' check +(-1) '.';
run;

OUTPUT:

/* Partial LOG output */
311 data _null_;
312 dsid=open('test');
313 check=varnum(dsid,'count');
314 if check=0 then put 'Variable does not exist';
315 else put 'Variable is located in column ' check +(-1) '.';
316 run;
Variable is located in column 2.
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds

source:www.support.sas.com