Python set 集合

1 >>> S1 = set(‘spiritman‘)
2 >>> print S1
3 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：增加一个元素到集合。当集合存在该元素时，该语句不生效
 2      Add an element to a set.This has no effect if the element is already present.
 3 语法：S.add(object)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S1.add(‘a‘)
 9 >>> print S1
10 set([‘a‘, ‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S1.add(‘a‘)
12 >>> print S1   
13 set([‘a‘, ‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])  

 1 功能：清空集合
 2      Remove all elements from this set.
 3 语法：S.clear()
 4 实例展示：
 5 >>>S1 = set(‘spirit‘)
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S1.clear()
 9 >>> print S1      
10 set([])

 1 功能：浅复制集合，返回一个新的集合。
 2      Return a shallow copy of a set.
 3 语法：S.copy()
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = S1.copy()
 9 >>> print S2
10 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> id(S2)
12 140239642434120
13 >>> print S1
14 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
15 >>> id(S1)
16 140239644667136

 1 功能：找出两个或多个集合中的不同元素，结果返回一个新的集合
 2      Return the difference of two or more sets as a new set.(all elements that are in this set but not the others.)
 3 语法：S.differencce(set1,set2.....)
 4 实例展示：
 5 >>> S1 = set(‘spirita‘) 
 6 >>> print S1           
 7 set([‘a‘, ‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spiri‘)   
 9 >>> print S2           
10 set([‘i‘, ‘p‘, ‘s‘, ‘r‘])
11 >>> S3 = set(‘liush‘) 
12 >>> print S3
13 set([‘i‘, ‘h‘, ‘s‘, ‘u‘, ‘l‘])
14 ##################################################
15 #找出S1和S2中的不同元素，结果返回一个新的集合
16 >>> S1.difference(S2)
17 set([‘a‘, ‘t‘])
18 ##################################################
19 #找出S1和S3中的不同元素，结果返回一个新的集合
20 >>> S1.difference(S3)
21 set([‘a‘, ‘p‘, ‘r‘, ‘t‘])
22 ##################################################
23 #找出S1、S2和S3中的不同元素，结果返回一个新的集合
24 >>> S1.difference(S2,S3)
25 set([‘a‘, ‘t‘])

 1 功能：删除集合S中所有跟S1中相同的元素。无相同元素时，各个集合不会发生改变。
 2      Remove all elements of another set from this set.
 3 语法：S.difference_update(S1)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘) 
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])     
 8 >>> S2 = set(‘abcde‘)       
 9 >>> print S2
10 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘])
11 >>> S3 = set(‘spiritman‘)  
12 >>> print S3
13 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
14 >>> S1.difference_update(S2)
15 >>> print S1
16 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
17 >>> print S2
18 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘])
19 >>> S1.difference_update(S3)
20 >>> print S1                
21 set([])
22 >>> print S3
23 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
24 >>> S2.difference_update(S3)
25 >>> print S2
26 set([‘c‘, ‘b‘, ‘e‘, ‘d‘])
27 >>> print S3                
28 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：从集合中删除一个元素。一次只能删除一个。
 2 　　  Remove an element from a set if it is a member.
 3 语法：S.discard(object)
 4 实例展示：
 5 S3 = set(‘spiritman‘)
 6 >>> print S3
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S3.discard(‘a‘)
 9 >>> print S3       
10 set([‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 ####################################################
12 #删除多个元素时报错
13  >>>S3.discard(‘i‘,‘m‘)
14 Traceback (most recent call last):
15   File "<stdin>", line 1, in <module>
16 TypeError: discard() takes exactly one argument (2 given)

 1 功能：求两个或多个集合的交集，交集返回一个新的集合。
 2 　　  Return the intersection of two or more sets as a new set.(elements that are common to all of the sets.)
 3 语法：S.intersection(set1,set2...)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)      
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spiman‘) 
 9 >>> print S2
10 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘])
11 >>> S3 = set(‘abcis‘)  
12 >>> print S3
13 set([‘a‘, ‘i‘, ‘c‘, ‘b‘, ‘s‘])
14 ##################################################
15 #求S1和S2的交集
16 >>> S1.intersection(S2)
17 set([‘i‘, ‘p‘, ‘s‘])
18 ##################################################
19 #求S1和S3的交集
20 >>> S1.intersection(S3)
21 set([‘i‘, ‘s‘])
22 ##################################################
23 #求S1、S2和S3的交集
24 >>> S1.intersection(S2,S3)
25 set([‘i‘, ‘s‘])

 1 功能： 以一个集合和另一个集合的交集更新该集合。
 2 　　   Update a set with the intersection of itself and another.
 3 语法：S.intersection_update(set1)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])   
 8 >>> S2 = set(‘spiman‘)
 9 >>> print S2
10 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘])
11 >>> S3 = set(‘abcis‘)
12 >>> print S3
13 set([‘a‘, ‘i‘, ‘c‘, ‘b‘, ‘s‘])
14 ##################################################
15 #以S1和S3的交集更新S1
16 >>> S1.intersection_update(S3) 
17 >>> print S1
18 set([‘i‘, ‘s‘])
19 ##################################################
20 #以S2和S3的交集更新S2
21 >>> S2.intersection_update(S3)
22 >>> print S2
23 set([‘a‘, ‘i‘, ‘s‘])

 1 功能：判断两个集合是否有集合。若没有则返回True；反之False。
 2      Return True if two sets have a null intersection.
 3 语法：S.isdisjoint(set1)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])   
 8 >>> S2 = set(‘spiman‘)
 9 >>> print S2
10 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘])
11 >>> S3 = set(‘abcdef‘)
12 >>> print S3
13 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘f‘])
14 ####################################################
15 >>> S1.isdisjoint(S2)
16 False
17 >>> S1.isdisjoint(S3)
18 True
19 >>> S2.isdisjoint(S3)
20 False

 1 功能：判断集合是否是另一个集合的子集合。是则返回True；反之False.
 2 　　  Report whether another set contains this set.
 3 语法：S.issubset(set1)
 4 实例展示：
 5 >>> S1 = set(‘spirit‘)   
 6 >>> print S1
 7 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spiritman‘)
 9 >>> print S2
10 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S3 = set(‘abcis‘)
12 >>> print S3
13 set([‘a‘, ‘i‘, ‘c‘, ‘b‘, ‘s‘])
14 ##################################################
15 >>> S1.issubset(S2)
16 True
17 >>> S3.issubset(S2)
18 False
19 >>> S1.issubset(S3)
20 False

 1 功能：判断集合是否包含另一个集合。
 2 　　  Report whether this set contains another set
 3 语法：issuperset(set1)
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spirit‘)   
 9 >>> print S2
10 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S1.issuperset(S2)
12 True

 1 功能：删除并返回任意一个元素。
 2 　　 Remove and return an arbitrary set element.Raises KeyError if the set is empty.
 3 语法：S.pop()
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 
 9 >>> S1.pop()   
10 ‘a‘
11 >>> S1.pop()
12 ‘i‘
13 >>> S1.pop()
14 ‘m‘
15 >>> print S1
16 set([‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：删除集合中一个指定的元素。
 2 　　  Remove an element from a set; it must be a member.If the element is not a member, raise a KeyError
 3 语法：S.remove(object)
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S1.remove(‘n‘)
 9 >>> print S1
10 set([‘a‘, ‘i‘, ‘m‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S1.remove(‘b‘)
12 Traceback (most recent call last):
13   File "<stdin>", line 1, in <module>
14 KeyError: ‘b‘

 1 功能：取两个集合的差集，返回一个新集合。
 2 Return the symmetric difference of two sets as a new set.(all elements that are in exactly one of the sets.)
 3 语法：S.symmetric_difference(set1)
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)      
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spirit‘)         
 9 >>> print S2
10 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S3 = set(‘bcde‘)           
12 >>> print S3
13 set([‘c‘, ‘b‘, ‘e‘, ‘d‘])
14 ##################################################
15 #返回S1和S2差集
16 >>> S1.symmetric_difference(S2)
17 set([‘a‘, ‘m‘, ‘n‘])
18 ##################################################
19 #返回S1和S3差集
20 >>> S1.symmetric_difference(S3)
21 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
22 ##################################################
23 #返回S2和S3差集
24 >>> S2.symmetric_difference(S3)
25 set([‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：取集合和另一个集合的差集，更新该集合。
 2 Update a set with the symmetric difference of itself and another.
 3 语法：symmetric_difference_update(set1)
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)      
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S2 = set(‘spirit‘)         
 9 >>> print S2
10 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
11 >>> S3 = set(‘bcde‘)           
12 >>> print S3
13 set([‘c‘, ‘b‘, ‘e‘, ‘d‘])
14 ####################################################
15 >>> S1.symmetric_difference_update(S2)
16 >>> print S1
17 set([‘a‘, ‘m‘, ‘n‘])
18 
19 >>> S2.symmetric_difference_update(S3)
20 >>> print S2
21 set([‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：取多个集合的并集，返回一个新的集合。
　　     Return the union of sets as a new set.(all elements that are in either set.)
 2 语法：S.union(set1,set2....)
 3 实例展示：
 4 >>> S1 = set(‘spiritman‘)      
 5 >>> print S1
 6 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 7 >>> S2 = set(‘spirit‘)         
 8 >>> print S2
 9 set([‘i‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
10 >>> S3 = set(‘bcde‘)           
11 >>> print S3
12 set([‘c‘, ‘b‘, ‘e‘, ‘d‘])
13 ##################################################
14 #返回S1和S2的并集
15 >>> S1.union(S2)
16 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
17 ##################################################
18 #返回S1和S3的并集
19 >>> S1.union(S3)
20 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
21 #################################################
22 #返回S1、S2和S3的并集
23 >>> S1.union(S2,S3)
24 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])

 1 功能：取一个集合和另一个集合的并集，更新该集合。
 2 　　  Update a set with the union of itself and others.
 3 语法：S.update(set1)
 4 实例展示：
 5 >>> S1 = set(‘spiritman‘)
 6 >>> print S1
 7 set([‘a‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])
 8 >>> S3 = set(‘bcde‘) 
 9 >>> print S3
10 set([‘c‘, ‘b‘, ‘e‘, ‘d‘])
11 >>> S1.update(S3)
12 >>> print S1
13 set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘, ‘i‘, ‘m‘, ‘n‘, ‘p‘, ‘s‘, ‘r‘, ‘t‘])