Re: Re: FindRoot question

*To*: mathgroup at smc.vnet.net*Subject*: [mg29933] Re: [mg29906] Re: FindRoot question*From*: Mianlai Zhou <lailai at nikhef.nl>*Date*: Thu, 19 Jul 2001 03:56:58 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On Wed, 18 Jul 2001, Chris Klausmeier wrote: > ListOfNumbersQ[list_]:=Module[{n,ret}, > If[ListQ[list]==False,ret=False, > n=Length[list]; > ret=True; > Do[ > If[NumberQ[list[[i]]]==False,ret=False] > ,{i,1,n}];]; Hi, I am sorry but I have to say, this version of ListOfNumbersQ is too bad. It is totally not functional and rule-based programming, which is an important feature of Mathematica. In fact, you can simply use: xopts:{___?NumberQ} to replace the xopts_?ListOfNumbersQ in your code. If you really want to define such a function, it may be implemented as ListOfNumbersQ[list_List] := And @@ NumberQ /@ list Good luck! Mianlai Zhou Theory Group, NIKHEF Amsterdam, The Netherlands