Re: Evaluation and replacement?
- To: mathgroup at smc.vnet.net
- Subject: [mg42505] Re: Evaluation and replacement?
- From: bobhanlon at aol.com (Bob Hanlon)
- Date: Sat, 12 Jul 2003 05:19:06 -0400 (EDT)
- References: <beln4d$gm0$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
f[expr_, r_Rule] := f[expr, r, Cases[r[[1]], _Symbol][[1]]];
f[expr_, r_Rule, var_Symbol] :=
Module[{a},
expr /. (Solve[r[[1]]==(r[[2]] /. var :> a),
var][[1]] /. a:>var)];
f[20m,10m->9m+n]//Expand
18 m+2 n
Bob Hanlon
In article <beln4d$gm0$1 at smc.vnet.net>, "AngleWyrm"
<no_spam_anglewyrm at hotmail.com> wrote:
<< Given a quantity 20m, and a rule 10m->9m+n, how can I get the result 18m+2n?
( m doesn't equal n; 10m degenerates into 9m + n. 9m doesn't degenerate into
8m+n.)