集合

set

建立空集合  a=set()

轉化一個數據爲集合：set（obj）,  注意數字不能直接轉化成集合，其餘均可以，只要是可迭代類型

set（一個字典），則集合內元素爲字典的鍵值：

關鍵是集合內置了去重，交集，並集，差集，對稱差集函數，這是別的數據類型沒有的

def  difference( self ,  * args,  * * kwargs):  # real signature unknown

   """

   Return the difference of two or more sets as a new set. A中存在，B中不存在

         

   (i.e. all elements that are in this set but not the others.)

   """

   pass

 

def  difference_update( self ,  * args,  * * kwargs):  # real signature unknown

　　 """ Remove all elements of another set from this set.  從當前集合中刪除和B中相同的元素"""

　　 pass

 

　　 def  discard( self ,  * args,  * * kwargs):  # real signature unknown

         """

　　 Remove an element from a set if it is a member.

         

   If the element is not a member, do nothing. 移除指定元素，不存在不保錯

   """

   pass

 

def  intersection( self ,  * args,  * * kwargs):  # real signature unknown

     """

   Return the intersection of two sets as a new set. 交集

         

   (i.e. all elements that are in both sets.)

   """

   pass

 

def  intersection_update( self ,  * args,  * * kwargs):  # real signature unknown

   """ Update a set with the intersection of itself and another.  取交集並更更新到A中 """

   pass

 

def  pop( self ,  * args,  * * kwargs):  # real signature unknown

   """

   Remove and return an arbitrary set element.

   Raises KeyError if the set is empty. 移除元素

   """

   pass

 

def  remove( self ,  * args,  * * kwargs):  # real signature unknown

   """

   Remove an element from a set; it must be a member.

         

   If the element is not a member, raise a KeyError. 移除指定元素，不存在保錯

   """

   pass

 

def  symmetric_difference( self ,  * args,  * * kwargs):  # real signature unknown

   """

   Return the symmetric difference of two sets as a new set.  對稱差集，全部差集，A中有B中沒有+B中有A中沒

         

   i.e. all elements that are in exactly one of the sets.)

   """

   pass

 

def  symmetric_difference_update( self ,  * args,  * * kwargs):  # real signature unknown

   """ Update a set with the symmetric difference of itself and another. 對稱差集，並更新到a中 """

   pass

 

def  union( self ,  * args,  * * kwargs):  # real signature unknown

   """

   Return the union of sets as a new set.  並集

         

   (i.e. all elements that are in either set.)

   """

   pass

 

def  update( self ,  * args,  * * kwargs):  # real signature unknown

   """ Update a set with the union of itself and others. 更新 """

   pass

 

實例：