1.描述

frozenset()返回一个冻结的集合，冻结后不能添加、删除和修改。
set()无序且不重复，是可以变的，有add、remove。扩展：删除重复数据，还可以计算交集、差集、并集等

2.函数用法

frozenset([iterable])iterable -- 可迭代对象，如：列表、字典、元组、字符串

3.返回值

返回新的frozenset对象，如果不提供任何参数，默认会生成空集合。

4.实例

'''&nbsp;frozenset&nbsp;'''num&nbsp;=&nbsp;frozenset(range(10))&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;创建不可变集合print(num)&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;frozenset({0,&nbsp;1,&nbsp;2,&nbsp;3,&nbsp;4,&nbsp;5,&nbsp;6,&nbsp;7,&nbsp;8,&nbsp;9})sitename&nbsp;=&nbsp;frozenset('pythonab')&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;创建不可变集合,&nbsp;注意：顺序不是按照参数的顺序print(sitename)&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;frozenset({'a',&nbsp;'b',&nbsp;'h',&nbsp;'p',&nbsp;'t',&nbsp;'y',&nbsp;'n',&nbsp;'o'})'''&nbsp;set&nbsp;'''sitename1&nbsp;=&nbsp;&nbsp;set('pythonab')&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;可变集合print(sitename1)&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;{'a',&nbsp;'b',&nbsp;'h',&nbsp;'p',&nbsp;'t',&nbsp;'y',&nbsp;'n',&nbsp;'o'}#&nbsp;set中向集合中添加sitename1.add('.com')print(sitename1)&nbsp;&nbsp;&nbsp;&nbsp;#&nbsp;{'.com',&nbsp;'a',&nbsp;'b',&nbsp;'h',&nbsp;'p',&nbsp;'t',&nbsp;'y',&nbsp;'n',&nbsp;'o'}#&nbsp;frozenset中向集合中添加成员sitename.add('.com')&nbsp;&nbsp;&nbsp;&nbsp;#向不可变集合中添加成员，会报错'''Traceback&nbsp;(most&nbsp;recent&nbsp;call&nbsp;last):&nbsp;&nbsp;File&nbsp;"<stdin>",&nbsp;line&nbsp;1,&nbsp;in&nbsp;<module>AttributeError:&nbsp;'frozenset'&nbsp;object&nbsp;has&nbsp;no&nbsp;attribute&nbsp;'add''''