class frozenset([iterable])
代码实验展示:
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul 8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license()" for more information. >>> # 可变集合 >>> s = set([1,2,3,4]) >>> s {1, 2, 3, 4} >>> s.add(5) >>> s {1, 2, 3, 4, 5} >>> >>> >>> # 不可变集合 >>> fs = frozenset([0,1,2,3,4]) >>> fs frozenset({0, 1, 2, 3, 4}) >>> fs.add(5) Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> fs.add(5) AttributeError: 'frozenset' object has no attribute 'add' >>> >>> >>> set("Happy") {'a', 'p', 'H', 'y'} >>> >>> frozenset("Happy") frozenset({'a', 'p', 'H', 'y'}) >>> >>>