Re: Operator that Adds Arguments
- To: mathgroup at smc.vnet.net
- Subject: [mg44847] Re: Operator that Adds Arguments
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Wed, 3 Dec 2003 04:24:42 -0500 (EST)
- Organization: The University of Western Australia
- References: <bqb7ch$nu6$1@bob.news.rcn.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <bqb7ch$nu6$1 at bob.news.rcn.net>,
"Scott Guthery" <sguthery at rcn.com> wrote:
> I've got a recursion that adds an argument at each step
> and I'd like to say something like ...
>
> L = Length[F]
> NextOne[F_] = Append[F, Function[F[[L]][#1, #2, ..., #L]+#[L+1]]]]
>
> and have F[[L+1]] be a function of L+1 arguments.
>
> Any suggestions?
Not sure what you're trying to do or why you would want this. Exactly
what sort of functional dependence are you looking for?
Anyway, here are some ideas about generating the left-hand side
(function name).
[1] Use a built-in function:
Append[f[], x]
f[x]
Append[%, y]
f[x, y]
Append[%, z]
f[x, y, z]
[2] If you have a list of arguments, say
v = {x, y, z, t};
then you could use NestList:
i = 1; NestList[Append[##,v[[++i]]] &, f[v[[i]]], Length[v] - 1]
{f[x], f[x, y], f[x, y, z], f[x, y, z, t]}
[3] Using FoldList avoids the use of a counter:
FoldList[Append, f[First[v]], Rest[v]]
{f[x], f[x, y], f[x, y, z], f[x, y, z, t]}
Cheers,
Paul
--
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