Re: Pattern Matching Problem
- To: mathgroup at smc.vnet.net
- Subject: [mg43415] Re: Pattern Matching Problem
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Tue, 16 Sep 2003 04:36:32 -0400 (EDT)
- Organization: The University of Western Australia
- References: <bihp1v$b3u$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <bihp1v$b3u$1 at smc.vnet.net>,
"Ersek, Ted R" <ErsekTR at navair.navy.mil> wrote:
> Consider the following:
>
> In[1]:=
> ClearAll[f,a,b,c,w,x,y,z];
> expr=a+b+c+f[w,2]+f[w,3]+x+f[x,2]+f[x,3]+y+f[y,2]+f[z,2];
>
>
> Can somebody suggest a general way to seperate the terms above into like
> groups. By "like" I mean having the same second argument for (f). So for
> this example I want to get
>
> {a+b+c+x+y, f[w,2]+f[x,2]+f[y,2]+f[z,2], f[w,3]+f[x,3]}
Not a full answer to your question, but one can get the partitioning you
are after using
Collect[expr /. c:f[_, n_] :> g[n] c, g[_]]
Cheers,
Paul
--
Paul Abbott Phone: +61 8 9380 2734
School of Physics, M013 Fax: +61 8 9380 1014
The University of Western Australia (CRICOS Provider No 00126G)
35 Stirling Highway
Crawley WA 6009 mailto:paul at physics.uwa.edu.au
AUSTRALIA http://physics.uwa.edu.au/~paul