Date:         Fri, 31 Aug 2001 14:47:15 -0600
Reply-To:     Jack Hamilton <JackHamilton@FIRSTHEALTH.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jack Hamilton <JackHamilton@FIRSTHEALTH.COM>
Subject:      Re: FW: Testing for empty file.
Comments: To: mdurbin@erac.com
Content-Type: text/plain; charset=us-ascii

If you're lucky.  Or nobs might be missing or wrong or some large but possibly plausible number if you're unlucky.

See <http://www2.sas.com/proceedings/sugi26/p095-26.pdf> for an examples.



--
JackHamilton@FirstHealth.com
Development Manager, Technical Group
METRICS Department, First Health
West Sacramento, California USA


>>> "Mike Durbin" <mdurbin@ERAC.COM> 08/31/2001 1:26 PM >>>
Here is the way I test for the number of observations in a file:

311  data _null_;
312    dsn = open('work.all');
313    nobs = attrn(dsn,'nobs');
314    rc = close(dsn);
315    put 'nobs = ' nobs;
316    run;

nobs = 2055
NOTE: DATA statement used:
      real time           0.00 seconds

The nobs variable will equal the number of observations in the file or -1 if
there are none.

Mike Durbin

-----Original Message-----
From: Jack Hamilton [mailto:JackHamilton@FIRSTHEALTH.COM]
Sent: Friday, August 31, 2001 2:42 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Re: Testing for empty file.


SAS will never set _N_ to blank; it will always be an integer >= 1.

If there are no records in the file, execution will stop at the first INPUT
statement, so the code below that will never execute.

You want to check whether the END= variable is true *before* you execute the
INPUT statement.

By the way, I recommend against calling your END= variable "EOF"  There's
also an EOF= option.  SAS won't get confused, but you might.  Using the EOF=
option is another way to handle your problem.




--
JackHamilton@FirstHealth.com
Development Manager, Technical Group
METRICS Department, First Health
West Sacramento, California USA


>>> "Valone, Toren W." <TValone@DMV.CA.GOV> 08/31/2001 11:55 AM >>>
How do I test for an empty file??
Here is my code below, It seems that if the file is empty, then Sas does not
populate the _n_ variable. I have also tried
a put all with no results.



//STEP030  EXEC SAS,OPTIONS='NONEWS'
//SASLOG   DD SYSOUT=*
//SASLIST  DD SYSOUT=*
//***************************************************************//
//* WRITES OUT ESP SYMBOLICS FOR RECEIVE JOB                    *//
//***************************************************************//
//ESPIN    DD DSN=&&ESP,DISP=(,PASS)
//ESPOUT   DD DSN=MV.PDG.EDI.ESP,DISP=OLD
//SYSIN    DD *
OPTIONS NOCENTER DQUOTE ;
DATA STEP1;
     INFILE ESPIN END = EOF;
     INPUT ;
     IF _N_ = '' THEN DO;
     PUT '_N_ IS BLANK';
     END;
     IF _N_ = 1  THEN DO;
     PUT '_N_ IS =1 ';
     END;