Re: pattern matching
- To: mathgroup at smc.vnet.net
- Subject: [mg7014] Re: pattern matching
- From: Dick Zacher <dick at loc3.tandem.com>
- Date: Thu, 1 May 1997 14:48:58 -0400 (EDT)
- Organization: Tandem Computers
- Sender: owner-wri-mathgroup at wolfram.com
Marc Mazzariol wrote: > > Hello, > > I'm using mathematica 2.2 (Unix), and i'm trying to do pattern > matching with repeated patterns. > > This example produce the result i want : > > In : {a,a,a,b} /. {a...,b} -> Hello > Out : Hello > > But this one don't : > > In : {b} /. {a...,b} -> Hello > Out : {b} > > I was hopping : Out : Hello > Marc, I ran into the same problem myself 5 years ago with version 2.0.4. It appeared to be a defect in the software: The function RepeatedNull did not work correctly -- it failed to match the absence of any element. I reported the problem to WRI at the time, but perhaps it did not get fixed in the next 2 releases. In Version 3.0 RepeatedNull does work and gives the results you were expecting. (I just tested it!) Dick -- ----------------------------- Dick Zacher Performance Engineering Dept., Tandem Computers zacher_dick at tandem.com phone: 408-285-5746 fax: 408-285-7079