Re: Question involving scope/recursion/arguments
- To: mathgroup at smc.vnet.net
- Subject: [mg27731] Re: Question involving scope/recursion/arguments
- From: "John Eric Hanson" <jhanson1 at stny.rr.com>
- Date: Tue, 13 Mar 2001 03:52:48 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Paul- One common example of what I'm trying to do is the quicksort algorithm - where a list or an array is sorted in place recursively. I am finding greta frustration trying to find the Mathematica technique which would result in behavior similar to passing an argument by reference or a pointer to an argument. I can do this with a global variable, but then, as far as I can see, I'm bound to passing in an argument with the same name as the global variable I'm using (else I have to make a copy of the variable unless Mathematica will allow two variables to reference the same data in memory - I'm obviously reasonably new to Mathematica). Thanks again, Eric > Well, you don't specify what you want to do, so I can only offer this > generic advice: > > f[list_,a_,b_] := (g[list], If[r, list = f[list_,c,d], STOP]) > > Or you can make the list global, not a passed argument. > > -- > Paul Lutus > www.arachnoid.com > > > >