s_a = set([1, 2, 3, 3, 4, 5, 6, 7, 7])
s_b = set([4, 5, 6, 7, 8, 9])
print(s_a)
print(s_b)
# 判断元素是否存在
print(8 in s_a)
print(8 in s_b)
# 并集
print(s_a | s_b)
print(s_a.union(s_b))
# 交集
print(s_a & s_b)
print(s_a.intersection(s_b))
# 差集 A - (A & B)
print(s_a - s_b)
print(s_a.difference(s_b))
# 对称差 (A | B) - (A & B)
print(s_a ^ s_b)
print(s_a.symmetric_difference(s_b))
# 修改元素
s_a.add('x')
print(s_a)
s_a.update([4, 5, 50, 60, 65, 70, 80])
print(s_a)
print('****')
s_a.add('y')
print(s_a)
s_a.remove(70)
print(s_a)
#s_a.remove(100)
print(len(s_a))
for i in s_a:
print(i)