Python集——intersection_update()函数

Python intersection_update()函数用于获取所有给定集合中存在的元素。它将删除所有集合中不存在的元素。

句法：

set.intersection_update(set1,set2,set3,...........,set n)

其中，set1、set2 是输入集。它可以采用任意数量的集合。

注意：要执行此函数，我们至少有两组。

示例：使用字符串元素定义两个集合的Python程序。

Python3

# declare set1
set1 = {"java", "python", "c/cpp", "html"}
  
# declare set2
set2 = {"php", "html", "java", "R"}
  
# display sets
print(set1, set2)
  
# perform intersection_update operation 
# on both the sets
set.intersection_update(set1, set2)
  
# display the result set
print(set1)

输出：

{‘c/cpp’, ‘python’, ‘html’, ‘java’} {‘php’, ‘R’, ‘html’, ‘java’}

{‘html’, ‘java’}

示例2：对多个集合的 intersection_update 操作。

Python3

# declare set1
set1 = {"java", "python", "c/cpp", "html"}
  
# declare set2
set2 = {"php", "html", "java", "R"}
  
# declare set3
set3 = {"java", "python", "ml", "dl"}
  
# declare set4
set4 = {"python", "java", "swift", "R"}
  
# display sets
print(set1, set2, set3, set4)
  
# perform intersection_update operation on
# all the sets
set.intersection_update(set1, set2, set3, set4)
  
# display the result set
print(set1)

输出：

{‘java’, ‘html’, ‘c/cpp’, ‘python’} {‘java’, ‘php’, ‘html’, ‘R’} {‘java’, ‘ml’, ‘dl’, ‘python’} {‘python’, ‘java’, ‘swift’, ‘R’}

{‘java’}

示例 3：

这里我们创建了两个集合，两个集合中没有共同的元素，所以输出应该是空的。在所有集合中，没有元素是共同的，因此输出是一个空集合。

Python3

# declare set1
set1 = {"java", "python", "c/cpp", "html"}
  
# declare set2
set2 = {"php", "cn", "dbms", "R"}
  
# display sets
print(set1, set2)
  
# perform intersection_update operation on 
# both the sets
set.intersection_update(set1, set2)
  
# display the result set
print(set1)

输出：

{‘java’, ‘python’, ‘c/cpp’, ‘html’} {‘R’, ‘cn’, ‘dbms’, ‘php’}

set()