How to convert a list of indexed variable names to a list of formal symbols?

Question

I have the following list of indexed variable names:

list = {x1,x2,x3,x4};

I would like to build a list of formal symbols from the above list, i.e.

{\[Formax1], \[Formax2], \[Formalx3], \[Formalx4]}

I've tried mapping Symbol to the names in the list, but it doesn't work. ㋡

Answer 1

I think you need to be very careful--you might not be able to get what you want. You mentioned that you're getting a list of symbols from a function. Let's mimic that:

symbolGenerator[] := {x1, x2, x3, x4};
symbolGenerator[]
(* returns {x1, x2, x3, x4} *)

Okay, let's say you wanted to use Unique on these so that you avoid name collisions. Well, it should work fine if none of the symbols were defined.

Unique[symbolGenerator[]]
(* {x1$7526, x2$7526, x3$7526, x4$7526} *)

But let's try again in a situation where there's actually a name collision:

ClearAll[x1, x2, x3, x4, symbolGenerator];
symbolGenerator[] := {x1, x2, x3, x4};
x3 = 17;
Unique[symbolGenerator[]]

Now we get a message saying "17 is not a symbol or a valid symbol name".

If you implemented symbolGenerator, then you could return strings instead of symbols; you could wrap the output in Hold or maybe Unevaluated; you could add a context directly to the symbols; or you could use Unique to start with. For example:

symbolGenerator[] := Unique[{"x1", "x2", "x3", "x4"}]
(* or *)
symbolGenerator[] := Symbol[StringJoin["special`", #]] & /@ {"x1", "x2", "x3", "x4"}

If you didn't implement symbolGenerator, then we'd probably need to know more about that function before making concrete suggestions.