Re: substitution within a substitution list
- To: mathgroup at smc.vnet.net
- Subject: [mg88597] Re: [mg88551] substitution within a substitution list
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 9 May 2008 03:26:18 -0400 (EDT)
- Reply-to: hanlonr at cox.net
Any one of these or similar variants
subs = subs /. (b -> _) -> (b -> 20)
subs = Join[Select[subs, FreeQ[#, b] &], {b -> 20}]
subs = Join[DeleteCases[subs, b -> _], {b -> 20}]
You can use Sort in the last two if the order matters to you.
Bob Hanlon
---- Bipin <bipin.caz at googlemail.com> wrote:
> HI,
>
> I'm trying to find a way of changing the substitution values within a
> substitution list.
>
> For example, if I have the following substitution list:-
>
> subs = {a->1, b->2, c->2}
>
> I want to programmatically replace the value associated with 'b' from
> 2 to 20, ie ending up with
>
> subs = {a->1, b->20, c->2}
>
> Does anyone know of a mathematica function for doing this?
>
> Bipin.
>