Re: Condition in replacement rule
- To: mathgroup at smc.vnet.net
- Subject: [mg67773] Re: [mg67736] Condition in replacement rule
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 7 Jul 2006 07:12:44 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
{A[V,W],A[V,V],A[V,x]}/.
A[V,W_/;Not[W===V]] -> A[V,W] + B[W]
{A(V,W)+B(W),A(V,V),A(V,x)+B(x)}
{A[V,W],A[V,V],A[V,x]}/.
A[V,W_]/;W=!=V -> A[V,W] + B[W]
{A(V,W)+B(W),A(V,V),A(V,x)+B(x)}
{A[V,W],A[V,V],A[V,x]}/.
A[V,W_?(#=!=V&)] -> A[V,W] + B[W]
{A(V,W)+B(W),A(V,V),A(V,x)+B(x)}
Bob Hanlon
---- "wandering.the.cosmos at gmail.com" <wandering.the.cosmos at gmail.com> wrote:
> I have a replacement rule that goes like
>
> A[V,W_] -> A[V,W] + B[W]
>
> but I want to perform this replacement if and only if V and W are not
> the same. It seems
>
> A[V,W_/;W!=V] -> A[V,W] + B[W]
>
> does not seem to work. How should I do this?
>
> Thanks!
>