集合 （set）

class set(object):
    """
    >>> li=set(['aaa','bbb','aaa'])
    >>> li
    {'aaa', 'bbb'}
    >>> st=set('aabccddf')
    >>> st
    {'a', 'b', 'd', 'c', 'f'}
    """
    def add(self, *args, **kwargs): #添加,把传入的元素作为一个整个添加进去
        >>> st.add('python')
        >>> st
        {'d', 'f', 'python', 'a', 'b', 'c'}
        
    def update(self, *args, **kwargs): # 更新，把传入的元素拆分然后传入集合
        """ 
        >>> s1=set('boy')
        >>> s1
        {'b', 'y', 'o'}
        >>> s1.update('python')
        >>> s1
        {'t', 'y', 'p', 'n', 'h', 'b', 'o'}
        """
        pass

    def clear(self, *args, **kwargs): # 清空
        >>> st.clear()
        >>> st
        set()
        pass

    def copy(self, *args, **kwargs): # 拷贝

    def difference(self, *args, **kwargs): #差集。在s1集合,不在s2集合的,操作后可以输出返回值
        >>> s1=set(['aaa','bbb'])
        >>> s2=set(['bbb','ccc'])
        >>> s1.difference(s2)
        {'aaa'}


    def difference_update(self, *args, **kwargs): #将s1更新为s1-s2的差集。没有返回值
        >>> s1
         {'aaa', 'bbb'}
        >>> s2
         {'bbb', 'ccc'}
        >>> s1.difference_update(s2)
        >>> s1
         {'aaa'}
        >>> s2
         {'bbb', 'ccc'}

    def discard(self, *args, **kwargs):  # 删除 
        
    def remove(self, *args, **kwargs): # 删除
     #set.remove(obj)和set.discard(obj)的区别在于，当obj存在于set中时，都将其删除；但当obj不存在于set中时，remove()会报错，discard()不会。

    def intersection(self, *args, **kwargs): # 交集 s1 & s2
        >>> s1=set(['aaa','bbb'])
        >>> s2=set(['bbb','ccc'])
        >>> d=s1.intersection(s2)
        >>> print(d)
         {'bbb'}

    def intersection_update(self, *args, **kwargs): # 交集 s1更新为这个值
    

    def isdisjoint(self, *args, **kwargs): # 没有交集
       >>> s1.isdisjoint(s2)
        False
 
    def issubset(self, *args, **kwargs): #  s1的每一个元素都在s2中
       >>> s1=set('abc')
       >>> s2=set('abcdef')
       >>> s1.issubset(s2)
        True
    def issuperset(self, *args, **kwargs): # s2的每一个元素都在s1中 
       >>> s1.issuperset(s2)
        False

    def pop(self, *args, **kwargs): # 删除
        """
        Remove and return an arbitrary set element.
        Raises KeyError if the set is empty.
        """
        pass

    def symmetric_difference(self, *args, **kwargs): # s1,s2的对称差，有返回值
        >>> s1=set(['aaa','bbb'])
        >>> s2=set(['bbb','ccc'])
        >>> d=s1.symmetric_difference(s2)
        >>> print(d)
         {'ccc', 'aaa'}

    def symmetric_difference_update(self, *args, **kwargs): # s1更新为s1,s2的对称差，没有返回值
        >>> s1=set(['aaa','bbb'])
        >>> s2=set(['bbb','ccc'])
        >>> s1.symmetric_difference_update(s2)
        >>> s1
         {'aaa', 'ccc'}

    def union(self, *args, **kwargs): # 并集  s1 | s2
        

set