Set symmetric difference

Question

Accepted Answer

The ^ operator on sets computes the symmetric difference - elements that are in one set or the other, but not both. 3 and 4 appear in both a and b, so they are excluded. 1 and 2 are only in a; 5 and 6 are only in b. Symmetric difference comes up whenever you need to find what changed between two snapshots - the elements unique to each side represent what was added or removed.