集合使用花括号将元素之间用逗号隔开即可。集合的输出里不会出现相同的元素。集合中有并集、交集、差集等，以下为一些简单的表达：
def main():
list1=[1,1,2,2,3,3]
print(list1)
set1={1,1,2,2,3,3}
print(set1)
set1.add(4)
set1.add(5)
print(set1)
set2={1,3,5,7,9}
print(set2)
set3=set1 & set2
#set3=set1.intersection(set2)
print(set3)
set3=set1 | set2
#st3=set1.union(set2)
print(set3)
set3=set1-set2
#set3=set1.difference(set2)
print(set3)
set3 = set2.difference(set1)
print(set3)
set3=set1 ^ set2
#set3=set1.symmetric_difference(set2)
print(set3)
for val in set2:
print(val)
print(set2.pop())
if 3 in set2:
set2.remove(3)
print(set2)
print(set2<=set1)
#print(set2.issubset(set1))
print(set1>=set2)
#print(set1.issuperset(set2))
if __name__ == ‘__main__‘:
main()
结果：
[1, 1, 2, 2, 3, 3]
{1, 2, 3}
{1, 2, 3, 4, 5}
{1, 3, 5, 7, 9}
{1, 3, 5}
{1, 2, 3, 4, 5, 7, 9}
{2, 4}
{9, 7}
{2, 4, 7, 9}
1
3
5
7
9
1
{5, 7, 9}
False
False