Re: Extracting just the value of the variable from the result of Solve/NDSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg62827] Re: Extracting just the value of the variable from the result of Solve/NDSolve*From*: Jean-Marc Gulliet <jeanmarc.gulliet at Gmail.com>*Date*: Tue, 6 Dec 2005 00:04:06 -0500 (EST)*Organization*: The Open University, Milton Keynes, UK*References*: <dmpa43$hl7$1@smc.vnet.net> <200512032352.SAA15963@smc.vnet.net> <dn22gp$kvb$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Pradeep Suresh wrote: > Hi all, > i am facing a peculiar problem with the curly brackets of the output of > Solve and NDsolve commands....the result of Solve/NSolve/DSolve/NDSolve > all are in the form of {{y->a}} format and at best by doing a y/.soln, i > can get it to {a}, but for my purposes of passing this result to > JAVA(using J/Link), i need the value of the variable as just 'a' and not > '{a}'(i hope i am making myself clear). > E.g. > eqn={F==2*T}; > T = 300; > sol = Solve[eqn, F] > F /. sol > > gives me {600}, as i said earlier i need the answer 600(which is > different in datatype compared to {600} even though for all practical > purposes {600} is the same as 600). When i use J/link to extract value, > the {600} is not considered an integer/string/double/function,...so i > cannnot use getInteger,getString etc. > Can someone plz suggest a solution this problem, however triveal as it > may sound, it is an important problem in using J/Link to talk with > Mathematica. > > Thank you very much in advance!! > Regards, > Pradeep > Hi Pradeep, Add a part specification to the the list of solutions {sol[[1]] in this case): In[1]:= eqn = F == 2*T; sol = Solve[eqn /. T -> 300, F]; F /. sol[[1]] Out[3]= 600