Re: Indexed variables

*To*: mathgroup at smc.vnet.net*Subject*: [mg24675] Re: Indexed variables*From*: Rainer Gruber <rainer.gruber at jk.uni-linz.ac.at>*Date*: Fri, 4 Aug 2000 01:19:00 -0400 (EDT)*Organization*: Johannes Kepler Universitaet Linz*References*: <8lsup5$26a@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Barbara Da Vinci wrote: > Hello, MathGroup > Is there anybody who knows as to thrust indexed > variables in Mathematica without assigning them a > value ? I need a[[1]] ... a[[8]] to be real headed > expressions (variables, if you like) present in some > equations as unknowns. > I tried a=Table[0,{k,1,8}] but it hampers me because > of zero value. > Goodbye > Barbara Da Vinci > > ______________________________________________________________________ > Do You Yahoo!? > Il tuo indirizzo gratis e per sempre @yahoo.it su http://mail.yahoo.it I have a simple solution for a list of indexed variables with string manipulation: First define a function h that yields a "quasi indexed" variable (the index is part of its name): In[1]:= h[i_Integer] := ToExpression["a" <> ToString[i]] With this function you can generate a list of variables, e. g. In[2]:= a = Table[h[i], {i, 1, 5}] Out[2]= {a1, a2, a3, a4, a5} You can refer to the variables as usual (as long as you don't assign anything else to "a"!) e. g.: In[3]:= a[[3]] Out[3]= a3 Rainer Gruber JOHANNES KEPLER UNIVERSITY LINZ Institute of Experimental Physics Atomic Physics and Surface Science (rainer.gruber at jk.uni-linz.ac.at)