Python-集合

一、集合的特性

1、集合是无序的，不能通过下标进行索引

2、集合有天生去重的功能

二、集合的运算

set1 = {1, 2, 3, 4, 5}
set2 = {5, 6, 7, 8, 9}
set_union = set1.union(set2) #并集，将set2合并到set1，并去掉重复元素
set_union1 = set1 | set2
set_intersection = set1.intersection(set2) #交集
set_intersection1 = set1 & set2
set_diff = set1.difference(set2) #差集
set_diff1 = set1 - set2
print('set1和set2的并集为： ', set_union)
print('set1 | set2 = ', set_union1)
print('set1和set2的交集为： ', set_intersection)
print('set1 & set2 = ', set_intersection1)
print('set1和set2的差集为： ', set_diff)
print('set1 - set2 = ', set_diff1)

查看结果：

set1和set2的并集为：  {1, 2, 3, 4, 5, 6, 7, 8, 9}
set1 | set2 =  {1, 2, 3, 4, 5, 6, 7, 8, 9}
set1和set2的交集为：  {5}
set1 & set2 =  {5}
set1和set2的差集为：  {1, 2, 3, 4}
set1 - set2 =  {1, 2, 3, 4}

三、集合的其他方法

set1 = set() #set()初始化集合, set1= {}初始化为字典
set1 = {1,2,3,4,5}
set2 = {3,4}
bool1 = set1.issubset(set2)  #判断set1是否为set2的子集
bool2 = set1.issuperset(set2) #判断set1是否为set2的父集
bool3 = set1.isdisjoint(set2) #判断是否有交集，没有交集返回True

set1 = {1,2,3,4,5}
set1.add(6) #添加元素
set1.remove(1) #删除指定元素
set1.pop() #随机删除一个元素
set1.discard(4) #删除指定元素