Intersection()函数Python

Python intersection()函数返回一个新集合，其中包含所有集合共有的元素

两个给定集合的交集是最大集合，它包含两个集合共有的所有元素。两个给定集合 A 和 B 的交集是由 A 和 B 共有的所有元素组成的集合。

交集的例子：

Input: Let set A = {2, 4, 5, 6}

       and set B = {4, 6, 7, 8}

Output: {4,6} 

Explanation: Taking the common elements in both the sets, we get {4,6} as the intersection of both the sets.

Python交集() 语法：

set1.intersection(set2, set3, set4….) 
In parameters, any number of sets can be given

Python交集()返回值：

The intersection() function returns a set, which has the intersection of all sets(set1, set2, set3…) with set1. It returns a copy of set1 only if no parameter is passed. 

Python交集() 示例

示例 1：set intersection() 的工作

Python3

# Python3 program for intersection() function
set1 = {2, 4, 5, 6}
set2 = {4, 6, 7, 8}
set3 = {4, 6, 8}
 
# union of two sets
print("set1 intersection set2 : ",
      set1.intersection(set2))
 
# union of three sets
print("set1 intersection set2 intersection set3 :",
      set1.intersection(set2, set3))

输出：

set1 intersection set2 :  {4, 6}
set1 intersection set2 intersection set3 : {4, 6}

示例 2： Python集合交集运算符(&)

我们也可以使用 &运算符获得交集。

Python3

# Python3 program for intersection() function
set1 = {2, 4, 5, 6}
set2 = {4, 6, 7, 8}
set3 = {1, 0, 12}
 
print(set1 & set2)
print(set1 & set3)
 
print(set1 & set2 & set3)

输出：

{4, 6}
set()
set()

示例 3： Python设置对面的交集

symmetric_difference() 与 set.intersection() 方法相反。

Python3

# Python3 program for intersection() function
set1 = {2, 4, 5, 6}
set2 = {4, 6, 7, 8}
set3 = {1, 0, 12}
 
print(set1.symmetric_difference(set2))
print(set1.symmetric_difference(set3))
print(set2.symmetric_difference(set3))

输出：

{2, 5, 7, 8}
{0, 1, 2, 4, 5, 6, 12}
{0, 1, 4, 6, 7, 8, 12}

示例 4： Python设置交集为空

Python3

set1 = {}
set2 = {}
 
# union of two sets
print("set1 intersection set2 : ",
      set(set1).intersection(set(set2)))

输出：

set1 intersection set2 :  set()