Mathematica 9 is now available
Student Support Forum
Student Support Forum: 'Names for general variables' topicStudent Support Forum > General > "Names for general variables"

< Previous CommentHelp | Reply To Comment | Reply To Topic
Author Comment/Response
Nicolette Caister
10/07/08 09:40am

In Response To 'Re: Names for general variables'
Hi again

Thank you for the info. I am battling to apply it to my work though. Please excuse me if I over explain or do not explain well enough. It is hard to write this up without the use of subscripts or superscripts!

I have tables called S0, S1, S2, etc. But I cannot call them "S0", at the moment I have Subscript[S,0] etc. From the previous response, I can see that I must use the ToExpression[] function. But this does not work in my notebook. I am using it in a ReplaceAll function.

(Here I name the table Subscript[S,i] where i is the number of times 'S' is differentiated w.r.t. p - in fact p is just a sort of "dummy variable")
From my differentiation I have S^(0,b)[t,p] which is S differentiated 0 times by t and 'b' times by p. I.e. standard notation for MM.

Before (to create the S_i's (S subscript i)) I had:
(mydiff function)/.{S^(0,b_)[t,p]->Subscript[S,b]}

this worked perfectly, and if S was differentiated twice, i had S_2. Exactly what I want. BUT, I now need to use the tables with files and instead of S_i I want plain Si. When I try this is my ReplaceAll (/.) part, it does not link the actual number, i, to the b, i.e., I have:
(mydiff function) /.{S^(0,b_)[t,p]->ToExpression["S",ToString[b]]}

This does not work - i get "Sb" in my expression instead of (for example) S2. What am I doing wrong?

Thank you for your help.

URL: ,

Subject (listing for 'Names for general variables')
Author Date Posted
Names for general variables Nicolette Ca... 09/15/08 06:45am
Re: Names for general variables Forum Modera... 09/20/08 9:28pm
Re: Re: Names for general variables Nicolette Ca... 10/07/08 09:40am
< Previous CommentHelp | Reply To Comment | Reply To Topic