       Re: Parse results from Solve

• To: mathgroup at smc.vnet.net
• Subject: [mg73919] Re: Parse results from Solve
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Sat, 3 Mar 2007 01:01:30 -0500 (EST)
• Organization: The Open University, Milton Keynes, UK
• References: <es916i\$2u2\$1@smc.vnet.net>

```nikki_74 wrote:
> I have used the Solve command to get the solutions for a system of equations. However I want to use these solutions in other commands, such as Reduce and Simplify.
>
> For instance, say the output of Solve is,
> sols= {{x->0,y->0},{x->1,y->2}}
>
> and I want all solutions where x!=y , or , all solutions where y>1.
>
> Can anybody help with this? Thanks!
>

You could use the Cases function as in the following.

In:=
sols = {{x -> 0, y -> 0}, {x -> 1, y -> 2}}

Out=
{{x -> 0, y -> 0}, {x -> 1, y -> 2}}

In:=
Cases[sols, {rx_, ry_} /; (x /. rx) != (y /. ry)]

Out=
{{x -> 1, y -> 2}}

In:=
Cases[sols, {rx_, ry_} /; (y /. ry) > 1]

Out=
{{x -> 1, y -> 2}}

Regards,
Jean-Marc

```

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