1.在尾部添加一项

    add(...)

    This has no effect if the element is already present

       >>> a = set([1,2,3,4,5])

       >>> a.add('shaw')

       >>> a

       set([1, 2, 3, 4, 5, 'shaw'])

2.清空集合中所有元素

    clear(...)

    Remove all elements from this set

        >>>a = set([1, 2, 3, 4, 5, 'shaw'])

        >>>a.clear()

        >>>a

        set([])

3.返回一个新集合,但是新集合中的元素,a中有,b中没有

    difference(...)

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> a.difference(b)

       set([1, 4, 'shaw'])

4.set a中删除,集合a和集合b同时拥有的元素

    difference_update(...)

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> a.difference_update(b)

       >>> a

       set([1, 4, 'shaw'])

       >>> b

       set([2, 3, 5, 'sam'])

5.删除set中指定元素(即使这个元素不存在与这个集合中,不会报错)

    discard(...)

    Remove an element from a set if it is amember.f the element is not a member, do nothing.

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> a.discard('5')

       >>> a

       set([1, 2, 3, 4, 5, 'shaw'])

       >>> a.discard('sam')

       >>> a

       set([1, 2, 3, 4, 5, 'shaw'])

 

6.返回一个新集合,新集合元素由set aset b的交集组成

    intersection(...)

    Return the intersection of two or more setsas a new set.

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> a.intersection(b) 等同于  a & b

       set([2, 3, 5])

7.set a中删除,ab交集之外的元素

    intersection_update(...)

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> a.intersection_update(b)

       >>> a

       set([2, 3, 5])

8.判断两个集合是否有交集,如果有,则返回True,否则返回False

    isdisjoint(...)

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> a.isdisjoint(b)

       False

       >>> c = set([9,'alices'])

       >>> a.isdisjoint(c)

       True

9.测试一个集合中的元素是否都在另一个元素中(即测试集合b是否是集合a的子集)

    issubset(...)

    Report whether another set contains this set

    注:

    issuperset(...)

    Report whether this set contains another set

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> b = set([2,3,5,'sam'])

       >>> c = set([5,'shaw'])

       >>> b.issubset(a)

       False

       >>> c.issubset(a)  等同于 c <= a

       True

10.删除一个元素(默认删除第一项),如果要删除的元素不存在,则报keyerror

    pop(...)

        >>>a = set([1, 2, 3, 4, 5, 'shaw'])

        >>>a.pop()

        1

        >>>a

        set([2,3, 4, 5, 'shaw'])

 

11. 删除指定元素,如果要删除的元素不存在,则报keyerror

    remove(...)

       >>> a = set([1, 2, 3, 4, 5,'shaw'])

       >>> a.remove(1)

       >>> a

       set([2, 3, 4, 5, 'shaw'])

       >>> a.remove('shaw')

       >>> a

       set([2, 3, 4, 5])

12.对称差集(此元素在a中有且b中没有,和b中有且a中没有的元素)

symmetric_difference(...)

       >>> a = set('abcdef')

       >>> b = set('abcklyt')

       >>> a.symmetric_difference(b)

       set(['e', 't', 'f', 'y', 'k', 'l', 'd'])

       >>> a ^ b

       set(['e', 't', 'f', 'y', 'k', 'l', 'd'])

13.取并集(返回一个新的 set 包含 s t 中的每一个元素)

    union(...)

       >>> a = set('acdf')

       >>> b = set('adkh')

       >>> a.union(b)

       set(['a', 'c', 'd', 'f', 'h', 'k'])

       >>> a | b

       set(['a', 'c', 'd', 'f', 'h', 'k'])

14.向集合a中添加元素(添加另一个集合时,会去除重复的元素)

    update(...)

       >>> a = set('acdf')

       >>> b = set('adkh')

       >>> a.update(b)

       >>> a

       set(['a', 'c', 'd', 'f', 'h', 'k'])

 

       >>> a = set('acdf')

       >>> b = set('adkh')

       >>> a |= b

       >>> a

       set(['a', 'c', 'd', 'f', 'h', 'k'])

 

       >>> a= set('shaw')

       >>> a.update('bnga')

       >>> a

       set(['a', 'b', 'g', 'h', 'n', 's', 'w'])