Re: Replacing Parts of a List

*To*: mathgroup at smc.vnet.net*Subject*: [mg28782] Re: [mg28742] Replacing Parts of a List*From*: Andrzej Kozlowski <andrzej at tuins.ac.jp>*Date*: Sat, 12 May 2001 20:18:14 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Sorry, I replied to the message too quickly without looking at my output and got thoroughly confused (because I was all the time misunderstanding your question). So my last message was all nonsense. What I meant was something like this: In[35]:= l=Subscript[a,{1,2,3}] Out[35]= a {1, 2, 3} In[39]:= l[[2,3]]=4; In[38]:= l Out[38]= a {1, 2, 4} In other words, you can change the subscripts in the same way as you change lists. Only later I understood that you are trying to use Sunscript[a,b] as a variable, and you want to change its values. The natural way to do so is to use the Notation package. Just copy everything below the dotted line below, paste into a new notebook and evaluate everything. It should be obvious what is going on. -- Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/ http://sigma.tuins.ac.jp/~andrzej/ on 01.5.12 0:45 PM, Andrzej Kozlowski at andrzej at tuins.ac.jp wrote: > As I tried to point out the first time, you can do: > > In[1]:= > l=Subscript[x,y]={1,2,3} > > Out[1]= > {1,2,3} > > In[2]:= > l[[3]]=10 > > Out[2]= > 10 > > In[3]:= > Subscript[x,y] > > Out[3]= > {1,2,3} > > I think this is really not that much more inconvenient than what you > originally tried to do, is it? > > -- > Andrzej Kozlowski > Toyama International University > JAPAN > > http://platon.c.u-tokyo.ac.jp/andrzej/ > http://sigma.tuins.ac.jp/~andrzej/ > > > on 01.5.12 10:40 AM, Jones, Roger M. at rmj at SLAC.Stanford.EDU wrote: > >> To clarify >> >> In[1]:=Subscript[x, y] = {1, 2, 3} >> >> Out1]={1, 2, 3} >> >> To replace the third element I must use : >> >> In[2]:=Subscript[x, y] = ReplacePart[Subscript[x, y], 10, 3] >> >> Out[2]={1, 2,10} >> >> So that now Subscript[x, y] gives: >> >> In[3]:=Subscript[x, y] >> >> Out[3]={1, 2, 10} >> >> >> This is unwieldy and I was hoping for a little more condensed notation. >> However, >> when using subscripts this appears appears to be the simplest notation >> available. >> >> -Roger Jones >> >> > ------------------------------------------------------------------ Notebook[{ Cell[BoxData[ \(<< Utilities`Notation`\)], "Input"], Cell[BoxData[ RowBox[{"Symbolize", "[", TagBox[\(a\_b\), NotationBoxTag, TagStyle->"NotationTemplateStyle"], "]"}]], "Input"], Cell[CellGroupData[{ Cell[BoxData[ \(a\_b = {1, 2, 3}\)], "Input"], Cell[BoxData[ \({1, 2, 3}\)], "Output"] }, Open ]], Cell[CellGroupData[{ Cell[BoxData[ \(a\_b[\([3]\)] = 10\)], "Input"], Cell[BoxData[ \(10\)], "Output"] }, Open ]], Cell[CellGroupData[{ Cell[BoxData[ \(a\_b\)], "Input"], Cell[BoxData[ \({1, 2, 10}\)], "Output"] }, Open ]] } ]