How to declare a variable with subscript being numbers?

Question

everyone! I hope to declare a variable with subscript as numbers, for example, $x_{10}$, $x_{11}$, $x_{01}$ as variables. Is it possible in mathematica? If so, how to implement it so that it treats $x_{10}$ as a variable? Thank you!

Hi ! You should add some details to your question, because it is not clear what you are actually trying to do. Add a simple (non)working example showing your goal, etc. — Sektor, Feb 05 '15 at 21:09
Although you can do something like this it is generally advised not to do this. But have a look at the Notation package if you really want this. — Sjoerd C. de Vries, Feb 05 '15 at 21:52

score 2 · Answer 1 · answered Feb 05 '15 at 22:16

2

Format[x[i_, j_]] :=
 Subscript[x, StringJoin[ToString /@ {i, j}]]

t = Total[{x[1, 0], x[1, 1], x[0, 1]}]

enter image description here

Solve[t == 1, x[0, 1]]

enter image description here

answered Feb 05 '15 at 22:16

Bob Hanlon

157,611
7
77
198

Jinxed · Answer 2 · 2015-03-08T14:23:51.253

Using the 'Notation' package, you can create real symbols from (not only!) subscripted variables:

Needs["Notation`"]

makesymbol[obj_]:=With[{},      
  If[NameQ@ToString@Unevaluated@obj,Remove@obj]; (* remove possibly existing symbol first *)
  Symbolize@ParsedBoxWrapper@ToBoxes@obj;]       (* then create the new symbol *)

With this function, you can create a symbol like so:

makesymbol[Subscript[x,"01"]]

Mathematica will now treat it the same as any other (simpler) symbol.

And the best part is:

You have the same look&feel everywhere, both in your code and the generated output.
It works for all kinds of notation, not only Subscript

I hope this might be of some help to you.

How to declare a variable with subscript being numbers?

2 Answers2