Telling Mathematica that a symbol is going to be a List?

*To*: mathgroup at smc.vnet.net*Subject*: [mg50817] Telling Mathematica that a symbol is going to be a List?*From*: AES/newspost <siegman at stanford.edu>*Date*: Wed, 22 Sep 2004 00:11:55 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I want to define a function containing parameters that are going to be elements in a list, e.g. something like m := { { d[[1]], 0, 0}, {0, d[[2]], 0}, {0, 0, d[[3]]} but not define the list of values of d until later (and not put the parameters in as explicit arguments of m just to keep the appearance less cluttered and typing easier). If I then give an input line m /. {d -> {d1, d2, d3} } // MatrixForm I get "Part::partd" errors -- but the matrix then displays correctly. I can of course just Off[] the errors -- but is there a better way.

**Follow-Ups**:**Re: Telling Mathematica that a symbol is going to be a List?***From:*"Maxim A. Dubinnyi" <maxim@nmr.ru>

**Re: Telling Mathematica that a symbol is going to be a List?***From:*Andrzej Kozlowski <andrzej@akikoz.net>

**Re: Telling Mathematica that a symbol is going to be a List?***From:*DrBob <drbob@bigfoot.com>