Re: Notation Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg47550] Re: Notation Question*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Thu, 15 Apr 2004 05:02:16 -0400 (EDT)*Organization*: The University of Western Australia*References*: <c5lfds$bqh$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <c5lfds$bqh$1 at smc.vnet.net>, scohen at cable.net.co (Sebastian Cohen S) wrote: > I need to make Mathematica understand that: > > Subscript[X,j] for j = 3 > > for example is Part[X,3] and more generally to understand that: > > the input should internally handle Subscript[exp, i,j] > as Part[exp, i,j] If x = {{a,b},{c,d},{e,f}}; then Subscript[x,j__] := x[[j]] does what you want. Note that you can use a subscripted form of indexing using [[ ]] _without_ any definitions. For example, if paste the following into a Notebook, Cell[BoxData[SubscriptBox["x", RowBox[{"\[LeftDoubleBracket]", "3", "\[RightDoubleBracket]"}]]], "Input"] and then evaluate it. This automatically works in the general case. Cheers, Paul -- Paul Abbott Phone: +61 8 9380 2734 School of Physics, M013 Fax: +61 8 9380 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul