Re: Solution of diff. equation i the form of list?

*To*: mathgroup at smc.vnet.net*Subject*: [mg5526] Re: [mg5517] Solution of diff. equation i the form of list?*From*: "w.meeussen" <w.meeussen at solair4b.eunet.be>*Date*: Thu, 19 Dec 1996 01:02:28 -0500*Sender*: owner-wri-mathgroup at wolfram.com

At 19:26 14-12-96 -0500, you wrote: >Hi! >Can you write how to get the solution of differential >equation in the form of list. >I tried to achievie it in that way: > >DSolve[{z'[x]==-z[x],z[0]==1},z[x],x] >data=Table[{x,z[x] /. %},{x,0.0,1.5,0.1}] > > and I got: > >{{z[x]->Exp[-x]}} >{{{0.0,{1.0}},{0.1,{0.8}}, etc > ^ ^ ^ ^ > >How to get rid of above extra {}'s? >If I use "data" list in "ListPlot[data]" function I got errors. > >If you know what to do please post or e-mail. > >Thanks in advance. > > Best regards > Wojtek Wlazlo > ufwlazlo at kinga.cyf-kr.edu.pl > > > hi Wojtek, simple : sol=DSolve[{z'[x]==-z[x],z[0]==1},z[x],x] data=Table[{x,z[x] /.Flatten[sol]},{x,0.0,1.5,0.1}] does what you need. What happened? DSolve generally gives a list of lists-of-rules as answer. Your case is simply a one-element list. The Wolframians wisely see it as the users task to extract the single element from its enveloping 'packaging'. Hence the Flatten[sol]. Don't despair, you'll get used to the style, and get to depend on its consistency. I wish you many more packaging to unwrap this christmas, Wouter. Dr. Wouter L. J. MEEUSSEN w.meeussen at solair4b.eunet.be