集合

基础使用

s  = set([1,2,3,3,3,3,3])

s = {1,2,3,4,5,5,5,}

判断是否是一个集合

创建集合	说明
`set(x)`	Create a set containing the elements of the collection “x”.`<br/>`
`frozenset(x)`	Create an immutable set containing the elements of the collection “x”.`<br/>`返回一个冻结的集合，冻结后集合不能再添加或删除任何元素。

管理集合	说明
`S.add(x)`	Add “x” to the set.
`S.update(s)`	Add all elements of sequence “s” to the set.
`S.remove(x)`	Remove “x” from the set. If “x” is not present, this method raises a `LookupError` exception.
`S.discard(x)`	Remove “x” from the set if it is present, or do nothing if it is not.
`S.pop()`	Remove and return an arbitrary element, raising a `LookupError` if the element is not present.
`S.clear()`	Remove all elements from this set.
`S.copy()`	Make a new set.
`s.issuperset()`	Check for a superset relationship.
`s.issubset()`	Check for a subset relationship.