Filter by variable type for use in suscripting.
Creates an object that can be used for subscripting into the variables dimension of a table and filtering on variable type.
type is the name of a type as charvec. This may be anything that
isa function accepts, or
'cellstr' to select cellstrs,
as determined by
Returns an object of an opaque type. Don’t worry about what type it is;
just pass it into the second argument of a subscript into a