Date:         Mon, 19 Jun 2006 11:31:41 -0600
Reply-To:     Alan Churchill <SASL001@SAVIAN.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Alan Churchill <SASL001@SAVIAN.NET>
Subject:      Re: Do regular expressions need to be declared in _n_=1
Comments: To: evilpettingzoo97@aol.com
In-Reply-To:  <8C861DCA7CB963B-84-B425@FWM-M29.sysops.aol.com>
Content-Type: text/plain; charset="utf-8"

Thank ken for the clarification.

So it seems that the best bet is to use the _n_=1 method to make sure the bases are always covered. That's what I needed to know.

Alan

Alan Churchill
Savian "Bridging SAS and Microsoft Technologies"
www.savian.net


-----Original Message-----
From: evilpettingzoo97@aol.com [mailto:evilpettingzoo97@aol.com]
Sent: Monday, June 19, 2006 11:27 AM
To: SASL001@savian.net; SAS-L@LISTSERV.UGA.EDU
Subject: Re: Do regular expressions need to be declared in _n_=1

Alan,

The compile once behavior of the PRX functions occurs if you use the /o modifier or in WHERE expressions. The /o modifier may not take in some cases when performing substitutions (with PRXCHANGE). Other than that, the other options are if _n_=1  & retain or a DoW loop.

HTH,
Ken

-----Original Message-----
From: Alan Churchill <SASL001@SAVIAN.NET>
To: SAS-L@LISTSERV.UGA.EDU
Sent: Mon, 19 Jun 2006 10:53:59 -0600
Subject: Do regular expressions need to be declared in _n_=1

  All,

I seem to recall at the last SUGI that regular expression patterns are automatically retained and are only processed once in a data step. For example,

Old Way:

Data test ;
       Infile ‘something or other’ ;
       Input;
       Retain pattern ;
       If _n_ = 1 then
           Do ;
                 Pattern = prxparse(“/some regex/”) ;
           End;
Run ;


Optional way:

Data test ;
       Infile ‘something or other’ ;
       Input;
       Pattern = prxparse(“/some regex/”) ; Run ;


Can anyone confirm this?

Thanks,
Alan

Alan Churchill
Savian "Bridging SAS and Microsoft Technologies"
www.savian.net


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