In Set or Not in Set? Frage zu Set.

[Klaus01]

Code:

The following operators take sets as operands.

Operator   Operation   Operand types   Result type   Example
+   union   set   set   Set1 + Set2
–   difference   set   set   S - T
*   intersection   set   set   S * T
<=   subset   set   Boolean   Q <= MySet
>=   superset   set   Boolean   S1 >= S2
=   equality   set   Boolean   S2 = MySet
<>   inequality   set   Boolean   MySet <> S1
in   membership   ordinal, set   Boolean   A in Set1

The following rules apply to +, –, and *.

An ordinal O is in X + Y if and only if O is in X or Y (or both). O is in X – Y if and only if O is in X but not in Y. O is in X * Y if and only if O is in both X and Y.
   The result of a +, –, or * operation is of the type set of A..B, where A is the smallest ordinal value in the result set and B is the largest.

The following rules apply to <=, >=, =, <>, and in.

X <= Y is True just in case every member of X is a member of Y; Z >= W is equivalent to W <= Z. U = V is True just in case U and V contain exactly the same members; otherwise, U <> V is True.
   For an ordinal O and a set S, O in S is True just in case O is a member of S.

wobei Intersection = Schnittmenge ist.

Grüße
Klaus