Re: Re: returning a variable's name, rather than the variable's contents

*To*: mathgroup at smc.vnet.net*Subject*: [mg68484] Re: [mg68461] Re: returning a variable's name, rather than the variable's contents*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Mon, 7 Aug 2006 01:40:55 -0400 (EDT)*References*: <eauvns$17c$1@smc.vnet.net> <200608060656.CAA23436@smc.vnet.net> <999EBD9F-124E-4F23-A9CF-56B249DBD8D5@mimuw.edu.pl>*Sender*: owner-wri-mathgroup at wolfram.com

On 6 Aug 2006, at 23:39, Andrzej Kozlowski wrote: > > On 6 Aug 2006, at 08:56, Peter Pein wrote: > >> Michael Stern schrieb: >>> There must be a simple way to do this but it eludes me. Take for >>> example the >>> following: >>> >>> >>> >>> In[2]:= a=1;b=2;c=3; >>> >>> >>> >>> In[3]:= Max[a,b,c] >>> >>> >>> >>> Out[3]= 3 >>> >>> >>> >>> What would I do if I wanted Out[3] to equal "c" ? >>> >>> >>> >>> Thanks in advance, >>> >>> >>> >>> Michael Stern >>> >>> >>> >> >> Hi Michael, >> >> I'm not familiar with the string functions in Mathematica. >> Therefore a much simpler approach will exist; but this one works: >> >> In[1]:= >> Attributes[nameOfMax] := {HoldAll}; >> nameOfMax[l__] := >> Module[{ls = StringJoin[", ", StringDrop[StringDrop[ToString >> [Unevaluated[l]], 9], -1], ","], sp}, >> sp = First /@ StringPosition[ls, ","]; >> StringTake[ls, sp[[{#1, #1 + 1}]] + {2, -1}]& [Last[Ordering >> [{l}]]]] >> In[3]:= >> {a, b, c, huge} = {1, 2, 3, 10^10}; >> In[4]:= >> nameOfMax[a, b, c] >> Out[4]= >> "c" >> In[5]:= >> nameOfMax[c, huge, a, b] >> Out[5]= >> "huge" >> >> HTH, >> Peter >> > > > One can achieve a similar effect without using any strings at all. > > Attributes[nameOfMax] := {HoldAll}; > > nameOfMax[p__] := With[ {l = Ordering[Flatten[List @@ > OwnValues /@ HoldForm[ > p]], -1, #1[[2]] <= #2[[2]] &]}, HoldForm[a, b, huge, c] > [[l]]] > > {a, b, huge, c} = {1, 2, 10^10, 3}; > > > nameOfMax[a, b, huge,c] > > huge > > > Andrzej Kozlowski Sorry, the correct code is of course: Attributes[nameOfMax] := {HoldAll}; nameOfMax[p__] := With[ {l = Ordering[Flatten[List @@ OwnValues /@ HoldForm[ p]], -1, #1[[2]] <= #2[[2]] &]}, HoldForm[p][[l]]] Andrzej Kozlowski

**References**:**Re: returning a variable's name, rather than the variable's contents***From:*Peter Pein <petsie@dordos.net>