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[1]:= sols = {{x -> 0, y -> 0}, {x -> 1, y -> 2}} Out[1]= {{x -> 0, y -> 0}, {x -> 1, y -> 2}} In[2]:= Cases[sols, {rx_, ry_} /; (x /. rx) != (y /. ry)] Out[2]= {{x -> 1, y -> 2}} In[3]:= Cases[sols, {rx_, ry_} /; (y /. ry) > 1] Out[3]= {{x -> 1, y -> 2}} Regards, Jean-Marc