Operations and Methods on Sets

Various operations can be executed on sets:

>>> A = set((3,78,43,2,9))

>>> B = set((2,89,7,9,78))

• membership testing: >>> 78 in A
• discard(): remove an element from a set, if it is member, if not do nothing: >>> A.discard(43)
• remove() functions like “discard” but “KeyError”, if element is not included Return the intersection of two sets as a new set: >>> A.intersection(B) {9, 2, 78} alternatively: >>> A & B {9, 2, 78}
• union, i.e. set.union() or “|”
• difference, i.e. set.difference() or “-”
• symmetric difference, i.e. set.symmetric_difference() or “^” the symmetric difference are all elements which are in exactly one of the sets.
• pop() removes and returns an arbitrary element from s; raises KeyError if empty
• clear() removes all elements from set s