参考链接： Python 集合set clear()
python 集合set的创建，更改，遍历，元算合并，交集，补集
set的创建，set不允许有重复的元素
s = set('cheershopa') 可以修改的set,
t = frozenset('bookshopa') 不可须该的set
r = set([1,2,3,34,15,25,35,45,75]) 列表转化到set
t = {} 空set
o = set([]) 空set
set的联合 交集 差补
s | t 求s 与 t的并集 结果和s的类型一样
s & t 求 s 与 t的交集，结果是s和类型一样
s - t 求 s 与 t 的差补 结果和s的类型一样
s.union(t)
s.intersection(t)
s.difference(t)
s.copy()
s.superset(t)
s.subset(t)
s |= t
s &= t
s -= t
set的内建方法help(set)
>>> help(set)
Help on class set in module __builtin__:
class set(object)
| set() -> new empty set object
| set(iterable) -> new set object
|
| Build an unordered collection of unique elements.
|
| Methods defined here:
|
| __and__(...)
| x.__and__(y) <==> x&y
|
| __cmp__(...)
| x.__cmp__(y) <==> cmp(x,y)
|
| __contains__(...)
| x.__contains__(y) <==> y in x.
|
| __eq__(...)
| x.__eq__(y) <==> x==y
|
| __ge__(...)
| x.__ge__(y) <==> x>=y
|
| __getattribute__(...)
| x.__getattribute__('name') <==> x.name
|
| __gt__(...)
| x.__gt__(y) <==> x>y
|
| __iand__(...)
| x.__iand__(y) <==> x&=y
|
| __init__(...)
| x.__init__(...) initializes x; see help(type(x)) for signature
|
| __ior__(...)
| x.__ior__(y) <==> x|=y
|
| __isub__(...)
| x.__isub__(y) <==> x-=y
|
| __iter__(...)
| x.__iter__() <==> iter(x)
|
| __ixor__(...)
| x.__ixor__(y) <==> x^=y
|
| __le__(...)
| x.__le__(y) <==> x<=y
|
| __len__(...)
| x.__len__() <==> len(x)
|
| __lt__(...)
| x.__lt__(y) <==> x<y
|
| __ne__(...)
| x.__ne__(y) <==> x!=y
|
| __or__(...)
| x.__or__(y) <==> x|y
|
| __rand__(...)
| x.__rand__(y) <==> y&x
|
| __reduce__(...)
| Return state information for pickling.
|
| __repr__(...)
| x.__repr__() <==> repr(x)
|
| __ror__(...)
| x.__ror__(y) <==> y|x
|
| __rsub__(...)
| x.__rsub__(y) <==> y-x
|
| __rxor__(...)
| x.__rxor__(y) <==> y^x
|
| __sizeof__(...)
| S.__sizeof__() -> size of S in memory, in bytes
|
| __sub__(...)
| x.__sub__(y) <==> x-y
|
| __xor__(...)
| x.__xor__(y) <==> x^y
|
| add(...)
| Add an element to a set.
|
| This has no effect if the element is already present.
|
| clear(...)
| Remove all elements from this set.
|
| copy(...)
| Return a shallow copy of a set.
|
| difference(...)
| Return the difference of two or more sets as a new set.
|
| (i.e. all elements that are in this set but not the others.)
|
| difference_update(...)
| Remove all elements of another set from this set.
|
| discard(...)
| Remove an element from a set if it is a member.
|
| If the element is not a member, do nothing.
|
| intersection(...)
| Return the intersection of two or more sets as a new set.
|
| (i.e. elements that are common to all of the sets.)
|
| intersection_update(...)
| Update a set with the intersection of itself and another.
|
| isdisjoint(...)
| Return True if two sets have a null intersection.
|
| issubset(...)
| Report whether another set contains this set.
|
| issuperset(...)
| Report whether this set contains another set.
|
| pop(...)
| Remove and return an arbitrary set element.
| Raises KeyError if the set is empty.
|
| remove(...)
| Remove an element from a set; it must be a member.
|
| If the element is not a member, raise a KeyError.
|
| symmetric_difference(...)
| Return the symmetric difference of two sets as a new set.
|
| (i.e. all elements that are in exactly one of the sets.)
|
| symmetric_difference_update(...)
| Update a set with the symmetric difference of itself and another.
|
| union(...)
| Return the union of sets as a new set.
|
| (i.e. all elements that are in either set.)
|
| update(...)
| Update a set with the union of itself and others.
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __hash__ = None
|
| __new__ = <built-in method __new__ of type object>
| T.__new__(S, ...) -> a new object with type S, a subtype of T
