Help on class frozenset in module __builtin__:
class frozenset(object)
| frozenset() -> empty frozenset object
| frozenset(iterable) -> frozenset object
|
| Build an immutable 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
|
| __hash__(...)
| x.__hash__() <==> hash(x)
|
| __iter__(...)
| x.__iter__() <==> iter(x)
|
| __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
|
| 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.)
|
| intersection(...)
| Return the intersection of two or more sets as a new set.
|
| (i.e. elements that are common to all of the sets.)
|
| 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.
|
| 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.)
|
| union(...)
| Return the union of sets as a new set.
|
| (i.e. all elements that are in either set.)
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __new__ = <built-in method __new__ of type object>
| T.__new__(S, ...) -> a new object with type S, a subtype of T
class frozenset([iterable])
Return a new frozenset object, optionally with elements taken from iterable. frozenset is a built-in class. See frozenset and Set Types — set, frozenset for documentation about this class.
For other containers see the built-in set, list, tuple, and dict classes, as well as the collections module.
中文说明：
本函数是返回一个冻结的集合。所谓冻结就是这个集合不能再添加或删除任何集合里的元素。
它是不可变的，存在哈希值，好处是它可以作为字典的key，也可以作为其它集合的元素。缺点是一旦创建便不能更改，没有add，remove方法。
>>> y=[1,2,3,4,5,6,7,8,9]
>>> print(len(y),y)
(9, [1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> set=frozenset(y)
>>> print(len(set),set)
(9, frozenset([1, 2, 3, 4, 5, 6, 7, 8, 9]))
>>> t=frozenset(‘bookshop‘)
>>> t
frozenset([‘b‘, ‘h‘, ‘k‘, ‘o‘, ‘p‘, ‘s‘])
>>> t=frozenset(‘bookshop‘)
>>> t
frozenset([‘b‘, ‘h‘, ‘k‘, ‘o‘, ‘p‘, ‘s‘])
>>> for i in t:
... print(i)
...
b
h
k
o
p
s
本文出自 “大云技术” 博客，请务必保留此出处http://hdlptz.blog.51cto.com/12553181/1900146
原文：http://hdlptz.blog.51cto.com/12553181/1900146