FiniteSet documentation inconsistent with usage in sympy

[eendebakpt]

The documentation for FiniteSet (https://github.com/sympy/sympy/blob/master/sympy/sets/sets.py#L1886) states that the FiniteSet: Represents a finite set of discrete numbers..

But in sympy itself the FiniteSet is used with non-integer arguments. Statements like FiniteSet('a', 'd', 'c') run fine.

[ritikBhandari]

Yes if that's the case it should be something like Represents a finite set of discrete elements of a particular type ig?

[oscarbenjamin]

There isn't really any "particular type". A FiniteSet is just a finite set of SymPy expressions. The set is uniquified through Eq bit the elements don't need to have any common type.

[asmeurer]

FiniteSet('a', 'd', 'c') actually creates a set of symbols because it is using string parsing. To create a set of strings you would need to have a symbolic expression type representing a string (we do have a Str class but I think it's only meant for internal use).

You're right though that set objects shouldn't be restricted to holding just numbers, or even just Expr, although perhaps it would be useful to make sets restricted a single kind of object at a time by default so that you can use FiniteSet.kind.