Date:         Wed, 7 Dec 2005 02:35:46 +0000
Reply-To:     toby dunn <tobydunn@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         toby dunn <tobydunn@HOTMAIL.COM>
Subject:      Re: Wild card equivalent in SAS ?
Comments: To: davidlcassell@MSN.COM
In-Reply-To:  <BAY103-F203C9CA47D3681525699C2B0430@phx.gbl>
Content-Type: text/plain; format=flowed

David,

Uhhhh clear as muddy water...



Toby Dunn





From: David L Cassell <davidlcassell@MSN.COM>
Reply-To: David L Cassell <davidlcassell@MSN.COM>
To: SAS-L@LISTSERV.UGA.EDU
Subject: Re: Wild card equivalent in SAS ?
Date: Tue, 6 Dec 2005 17:06:11 -0800

stringplayer_2@YAHOO.COM replied:
>You aren't exactly clear about what you need to accomplish.
>You speak of replacing TEXT in lines where 'mening.TEXT.W135'
>is true.  Are you reading a flat file where and rewriting
>the flat file, updating records where the entire line
>follows the specified template?
>
>If so, and if you read the entire line as a single variable
>named LINE, then the scan function could be employed to
>identify records which need to be updated.  This is quite
>easy, assuming a recent version of SAS, say V8.x and above.
>You can scan for the first word delimited by a '.' and
>scan for the last word delimited by a '.'.  Having identified
>a line which needs to be replaced, you can rewrite the line
>concatenating 'mening.' and '.W135' with replacement text
>sandwiched in between.
>
>     if scan(line,1,'.')='mening' AND
>        scan(line,-1,'.')='W135' then
>        line = 'mening.' || '<replacement text>' || '.W135';
>
>David Cassell will undoubtedly offer up a Perl regular
>expression (PRX??? function) which will accomplish the
>identification and replacement all implemented in a single
>call routine.  It will be very elegant, but if you don't
>know PRX functions, it will take you the better part of
>a week to figure out just how the function works.

I'm hurt.  I thought that my PRX posts were as clear as water.  :-)  :-)

If our poster has 9.1, he can stuff the regex inside the PRXMATCH() function
and do this in one line of UNTESTED code:

  if prxmatch('/mening\.\w+\.W135/', VarToBeChecked);


Now isn't that simple?  The regex inside the forward slashes says:

mening    the letters 'mening'
\.        a real period
\w+       one or more 'word' characters: A-Z, a-z, 0-9, or _
\.        another real period
W135      the sequence 'W135'

I personally prefer some error checking.  The below code works as long as
you have
SAS 9:


data newstuff;
  retain re;
  set oldstuff;
  if _n_=1 then do;
    re = prxparse('/mening\.\w+\.W135/');
    if missing(re) then do; putlog 'ERROR: evil regex loose!'; stop; end;
    end;
  if prxmatch(re, VarToBeChecked);
  run;


David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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