![](\"https:\/\/p3-sign.toutiaoimg.com\/dfic-imagehandler\/32a3264a-9567-4f1b-a45b-705d4c881ee9~tplv-tt-large.image?x-expires=1971612059&x-signature=4u%2BmaLCBDQq3Cunoiov1vBJrxr4%3D&\/1.jpg\")
<\/p>\n<\/p>\n
\n\u3000\u3000\u5a1c\u7c73\u8207\u6200\u611b\u5c0f\u79d8\u66f8\u5011\u6700\u8fd1\u6574\u7406\u4e86\u4e00\u5957Python\u5b78\u7fd2\u6559\u7a0b\uff0c\u6709\u9700\u8981\u7684\u5c0f\u5925\u4f34\uff0c\u8a18\u5f97\u95dc\u8a3b\u5a1c\u7c73\u8207\u6200\u611b\u5c0f\u79d8\u66f8\u5011\u982d\u689d\u865f\uff0c\u79c1\u4fe1\u3010\u5b78\u7fd2\u3011\u5373\u53ef\u514d\u8cbb\u9818\u53d6\u4e00\u5957Python\u5b78\u7fd2\u6559\u7a0b\u54e6<\/p>\n<\/blockquote>\n
\u3000\u3000__str__<\/strong><\/p>\n
\u3000\u3000\u6539\u8b8a\u5c0d\u8c61\u7684\u5b57\u7b26\u4e32\u986f\u793a\u3002\u53ef\u4ee5\u7406\u89e3\u70ba\u4f7f\u7528print\u51fd\u6578\u5217\u5370\u4e00\u500b\u5c0d\u8c61\u6642\uff0c\u6703\u81ea\u52d5\u8abf\u7528\u5c0d\u8c61\u7684__str__\u65b9\u6cd5<\/p>\n
\u3000\u3000class Student: def __init__(self, name, age): self.name = name self.age = age # \u5b9a\u7fa9\u5c0d\u8c61\u7684\u5b57\u7b26\u4e32\u8868\u793a def __str__(self): return self.name s1 = Student(‘\u5f35\u4e09’, 24)print(s1) # \u6703\u8abf\u7528s1\u7684__str__\u65b9\u6cd5<\/pre>\n
\u3000\u3000__repr__<\/strong><\/p>\n
\u3000\u3000\u5728python\u89e3\u91cb\u5668\u74b0\u5883\u4e0b\uff0c\u6703\u9ed8\u8a8d\u986f\u793a\u5c0d\u8c61\u7684repr\u8868\u793a\u3002<\/p>\n
\u3000\u3000>>> class Student:… def __init__(self, name, age):… self.name = name… self.age = age… def __repr__(self):… return self.name… >>> s1 = Student(‘\u5f35\u4e09’, 24)>>> s1\u5f35\u4e09<\/pre>\n
\u3000\u3000\u7e3d\u7d50\uff1a<\/p>\n
\u3000\u3000str\u51fd\u6578\u6216\u8005print\u51fd\u6578\u8abf\u7528\u7684\u662fobj.__str__()<\/p>\n
\u3000\u3000repr\u51fd\u6578\u6216\u8005\u4ea4\u4e92\u5f0f\u89e3\u91cb\u5668\u8abf\u7528\u7684\u662fobj.__repr__()<\/p>\n
\u3000\u3000\u6ce8\u610f\uff1a<\/p>\n
\u3000\u3000\u5982\u679c__str__\u6c92\u6709\u88ab\u5b9a\u7fa9\uff0c\u90a3\u9ebc\u5c31\u6703\u4f7f\u7528__repr__\u4f86\u4ee3\u66ff\u8f38\u51fa\u3002<\/p>\n
\u3000\u3000__str__\u548c__repr__\u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u90fd\u5fc5\u9808\u662f\u5b57\u7b26\u4e32\u3002<\/p>\n
\u3000\u3000__format__<\/strong><\/p>\n
\u3000\u3000class Student: def __init__(self, name, age): self.name = name self.age = age __format_dict = { ‘n-a’: ‘\u540d\u5b57\u662f\uff1a{obj.name}-\u5e74\u9f61\u662f\uff1a{obj.age}’, # \u540d\u5b57\u662f\uff1alqz-\u5e74\u9f61\u662f\uff1a18 ‘n:a’: ‘\u540d\u5b57\u662f\uff1a{obj.name}\uff1a\u5e74\u9f61\u662f\uff1a{obj.age}’, # \u540d\u5b57\u662f\uff1alqz\uff1a\u5e74\u9f61\u662f\uff1a18 ‘n\/a’: ‘\u540d\u5b57\u662f\uff1a{obj.name}\/\u5e74\u9f61\u662f\uff1a{obj.age}’, # \u540d\u5b57\u662f\uff1a\/\u5e74\u9f61\u662f\uff1a18 } def __format__(self, format_spec): if not format_spec or format_spec not in self.__format_dict: format_spec = ‘n-a’ fmt = self.__format_dict[format_spec] print(fmt) #{obj.name}:{obj.age} return fmt.format(obj=self)s1 = Student(‘lqz’, 24)ret = format(s1, ‘n\/a’)print(ret) # lqz\/24<\/pre>\n
\u3000\u3000__del__<\/strong><\/p>\n
\u3000\u3000\u6790\u69cb\u65b9\u6cd5\uff0c\u7576\u5c0d\u8c61\u5728\u8a18\u61b6\u9ad4\u4e2d\u88ab\u91cb\u653e\u6642\uff0c\u81ea\u52d5\u89f8\u767c\u57f7\u884c\u3002<\/p>\n
\u3000\u3000\u8a3b\uff1a\u6b64\u65b9\u6cd5\u4e00\u822c\u7121\u9808\u5b9a\u7fa9\uff0c\u56e0\u70baPython\u662f\u4e00\u9580\u9ad8\u7d1a\u8a9e\u8a00\uff0c\u8cc7\u8a0a\u5de5\u7a0b\u5e2b\u5728\u4f7f\u7528\u6642\u7121\u9700\u95dc\u5fc3\u8a18\u61b6\u9ad4\u7684\u5206\u914d\u548c\u91cb\u653e\uff0c\u56e0\u70ba\u6b64\u5de5\u4f5c\u90fd\u662f\u4ea4\u7d66Python\u89e3\u91cb\u5668\u4f86\u57f7\u884c\uff0c\u6240\u4ee5\u6790\u69cb\u51fd\u6578\u7684\u8abf\u7528\u662f\u7531\u89e3\u91cb\u5668\u5728\u9032\u884c\u5783\u573e\u56de\u6536\u6642\u81ea\u52d5\u89f8\u767c\u57f7\u884c\u7684\u3002<\/p>\n
\u3000\u3000class A: def __del__(self): print(‘\u522a\u9664\u4e86…’)a = A()print(a) # del a # \u522a\u9664\u4e86…print(a) # NameError: name ‘a’ is not defined<\/pre>\n
\u3000\u3000__dict__\u548c__slots__<\/strong><\/p>\n
\u3000\u3000Python\u4e2d\u7684\u985e\uff0c\u90fd\u6703\u5f9eobject\u88e1\u7e7c\u627f\u4e00\u500b__dict__\u5c6c\u6027\uff0c\u9019\u500b\u5c6c\u6027\u4e2d\u5b58\u653e\u8457\u985e\u7684\u5c6c\u6027\u548c\u65b9\u6cd5\u5c0d\u61c9\u7684\u9375\u503c\u5c0d\u3002\u4e00\u500b\u985e\u5be6\u4f8b\u5316\u4e4b\u5f8c\uff0c\u9019\u500b\u985e\u7684\u5be6\u4f8b\u4e5f\u5177\u6709\u9019\u9ebc\u4e00\u500b__dict__\u5c6c\u6027\u3002\u4f46\u662f\u4e8c\u8005\u4e26\u4e0d\u76f8\u540c\u3002<\/p>\n
\u3000\u3000class A: some = 1 def __init__(self, num): self.num = numa = A(10)print(a.__dict__) # {‘num’: 10}a.age = 10print(a.__dict__) # {‘num’: 10, ‘age’: 10}<\/pre>\n
\u3000\u3000\u5f9e\u4e0a\u9762\u7684\u4f8b\u5b50\u53ef\u4ee5\u770b\u51fa\u4f86\uff0c\u5be6\u4f8b\u96bb\u4fdd\u5b58\u5be6\u4f8b\u7684\u5c6c\u6027\u548c\u65b9\u6cd5\uff0c\u985e\u7684\u5c6c\u6027\u548c\u65b9\u6cd5\u5b83\u662f\u4e0d\u4fdd\u5b58\u7684\u3002\u6b63\u662f\u7531\u65bc\u985e\u548c\u5be6\u4f8b\u6709__dict__\u5c6c\u6027\uff0c\u6240\u4ee5\u985e\u548c\u5be6\u4f8b\u53ef\u4ee5\u5728\u904b\u884c\u904e\u7a0b\u52d5\u614b\u6dfb\u52a0\u5c6c\u6027\u548c\u65b9\u6cd5\u3002<\/p>\n
\u3000\u3000\u4f46\u662f\u7531\u65bc\u6bcf\u5be6\u4f8b\u5316\u4e00\u500b\u985e\u90fd\u8981\u5206\u914d\u4e00\u500b__dict__\u8b8a\u91cf\uff0c\u5bb9\u6613\u6d6a\u8cbb\u8a18\u61b6\u9ad4\u3002\u56e0\u6b64\u5728Python\u4e2d\u6709\u4e00\u500b\u5167\u7f6e\u7684__slots__\u5c6c\u6027\u3002\u7576\u4e00\u500b\u985e\u8a2d\u7f6e\u4e86__slots__\u5c6c\u6027\u5f8c\uff0c\u9019\u500b\u985e\u7684__dict__\u5c6c\u6027\u5c31\u4e0d\u5b58\u5728\u4e86\uff08\u540c\u7406\uff0c\u8a72\u985e\u7684\u5be6\u4f8b\u4e5f\u4e0d\u5b58\u5728__dict__\u5c6c\u6027\uff09\uff0c\u5982\u6b64\u4e00\u4f86\uff0c\u8a2d\u7f6e\u4e86__slots__\u5c6c\u6027\u7684\u985e\u7684\u5c6c\u6027\uff0c\u53ea\u80fd\u662f\u9810\u5148\u8a2d\u5b9a\u597d\u7684\u3002<\/p>\n
\u3000\u3000\u7576\u4f60\u5b9a\u7fa9__slots__\u5f8c\uff0c__slots__\u5c31\u6703\u70ba\u5be6\u4f8b\u4f7f\u7528\u4e00\u7a2e\u66f4\u52a0\u7dca\u6e4a\u7684\u5167\u90e8\u8868\u793a\u3002\u5be6\u4f8b\u901a\u904e\u4e00\u500b\u5f88\u5c0f\u7684\u56fa\u5b9a\u5927\u5c0f\u7684\u5c0f\u578b\u6578\u7d44\u4f86\u69cb\u5efa\u7684\uff0c\u800c\u4e0d\u662f\u70ba\u6bcf\u500b\u5be6\u4f8b\u90fd\u5b9a\u7fa9\u4e00\u500b__dict__\u5b57\u5178\uff0c\u5728__slots__\u4e2d\u5217\u51fa\u7684\u5c6c\u6027\u540d\u5728\u5167\u90e8\u88ab\u6620\u5c04\u5230\u9019\u500b\u6578\u7d44\u7684\u7279\u5b9a\u7d22\u5f15\u4e0a\u3002\u4f7f\u7528__slots__\u5e36\u4f86\u7684\u526f\u4f5c\u7528\u662f\u6211\u5011\u6c92\u6709\u8fa6\u6cd5\u7d66\u5be6\u4f8b\u6dfb\u52a0\u4efb\u4f55\u65b0\u7684\u5c6c\u6027\u4e86\u3002<\/p>\n
\u3000\u3000\u6ce8\u610f\uff1a\u76e1\u7ba1__slots__\u770b\u8d77\u4f86\u662f\u500b\u975e\u5e38\u6709\u7528\u7684\u7279\u6027\uff0c\u4f46\u662f\u9664\u975e\u4f60\u5341\u5206\u78ba\u5207\u7684\u77e5\u9053\u8981\u4f7f\u7528\u5b83\uff0c\u5426\u5247\u76e1\u91cf\u4e0d\u8981\u4f7f\u7528\u5b83\u3002\u4f8b\u5982\u5b9a\u7fa9\u4e86__slots__\u5c6c\u6027\u7684\u985e\u5c31\u4e0d\u652f\u6301\u591a\u7e7c\u627f\u3002__slots__\u901a\u5e38\u90fd\u662f\u4f5c\u70ba\u4e00\u7a2e\u512a\u5316\u5de5\u5177\u4f86\u4f7f\u7528\u3002–\u6458\u81ea\u300aPython Cookbook\u300b8.4<\/p>\n
\u3000\u3000class A: __slots__ = [‘name’, ‘age’] a1 = A()# print(a1.__dict__) # AttributeError: ‘A’ object has no attribute ‘__dict__’a1.name = ‘\u5f35\u4e09’a1.age = 24# a1.hobby = ‘\u6ce1\u599e’ # AttributeError: ‘A’ object has no attribute ‘hobby’print(a1.__slots__)<\/pre>\n
\u3000\u3000\u6ce8\u610f\u4e8b\u9805\uff1a<\/p>\n
\u3000\u3000__slots__\u7684\u5f88\u591a\u7279\u6027\u90fd\u4f9d\u8cf4\u65bc\u666e\u901a\u7684\u57fa\u65bc\u5b57\u5178\u7684\u5be6\u73fe\u3002<\/p>\n
\u3000\u3000\u53e6\u5916\uff0c\u5b9a\u7fa9\u4e86__slots__\u5f8c\u7684\u985e\u4e0d\u518d \u652f\u6301\u4e00\u4e9b\u666e\u901a\u985e\u7279\u6027\u4e86,\u4f8b\u5982\u591a\u7e7c\u627f\u3002\u5927\u591a\u6578\u60c5\u6cc1\u4e0b,\u4f60\u61c9\u8a72\u96bb\u5728\u90a3\u4e9b\u7d93\u5e38\u88ab\u4f7f\u7528\u5230\u7684\u7528\u4f5c\u6578\u64da\u7d50\u69cb\u7684\u985e\u4e0a\u5b9a\u7fa9__slots__\uff0c\u4f8b\u5982\u5728\u7a0b\u5e8f\u4e2d\u9700\u8981\u5275\u5efa\u67d0\u500b\u985e\u7684\u5e7e\u767e\u842c\u500b\u5be6\u4f8b\u5c0d\u8c61 \u3002<\/p>\n
\u3000\u3000\u95dc\u65bc__slots__\u7684\u4e00\u500b\u5e38\u898b\u932f\u8aa4\u662f\u5b83\u53ef\u4ee5\u4f5c\u70ba\u4e00\u500b\u5c01\u88dd\u5de5\u5177\u4f86\u9632\u6b62\u7528\u6236\u7d66\u5be6\u4f8b\u589e\u52a0\u65b0\u7684\u5c6c\u6027\u3002\u76e1\u7ba1\u4f7f\u7528__slots__\u53ef\u4ee5\u9054\u5230\u9019\u6a23\u7684\u76ee\u7684,\u4f46\u662f\u9019\u500b\u4e26\u4e0d\u662f\u5b83\u7684\u521d\u8877\u3002\u5b83\u66f4\u591a\u7684\u662f\u7528\u4f86\u4f5c\u70ba\u4e00\u500b\u8a18\u61b6\u9ad4\u512a\u5316\u5de5\u5177\u3002<\/p>\n
\u3000\u3000__item__\u7cfb\u5217<\/strong><\/p>\n
\u3000\u3000class Foo: def __init__(self, name): self.name = name def __getitem__(self, item): print(self.__dict__[item]) def __setitem__(self, key, value): print(‘obj[key]=lqz\u8ce6\u503c\u6642\uff0c\u57f7\u884c\u6211’) self.__dict__[key] = value def __delitem__(self, key): print(‘del obj[key]\u6642\uff0c\u57f7\u884c\u6211’) self.__dict__.pop(key) def __delattr__(self, item): print(‘del obj.key\u6642\uff0c\u57f7\u884c\u6211’) self.__dict__.pop(item)f1 = Foo(‘sb’)print(f1.__dict__)f1[‘age’] = 18f1.hobby = ‘\u6ce1\u599e’del f1.hobbydel f1[‘age’]f1[‘name’] = ‘lqz’print(f1.__dict__)<\/pre>\n
\u3000\u3000__init__<\/strong><\/p>\n
\u3000\u3000\u4f7f\u7528Python\u5beb\u9762\u5411\u5c0d\u8c61\u7684\u4ee3\u78bc\u7684\u6642\u5019\u6211\u5011\u90fd\u6703\u7fd2\u6163\u6027\u5beb\u4e00\u500b __init__ \u65b9\u6cd5\uff0c__init__ \u65b9\u6cd5\u901a\u5e38\u7528\u5728\u521d\u59cb\u5316\u4e00\u500b\u985e\u5be6\u4f8b\u7684\u6642\u5019\u3002\u4f8b\u5982\uff1a<\/p>\n
\u3000\u3000class Person: def __init__(self, name, age): self.name = name self.age = age def __str__(self): return ‘‘.format(self.name, self.age)p1 = Person(‘\u5f35\u4e09’, 24)print(p1)<\/pre>\n
\u3000\u3000\u4e0a\u9762\u662f__init__\u6700\u666e\u901a\u7684\u7528\u6cd5\u4e86\u3002\u4f46\u662f__init__\u5176\u5be6\u4e0d\u662f\u5be6\u4f8b\u5316\u4e00\u500b\u985e\u7684\u6642\u5019\u7b2c\u4e00\u500b\u88ab\u8abf\u7528\u7684\u65b9\u6cd5\u3002\u7576\u4f7f\u7528 Persion(name, age) \u4f86\u5be6\u4f8b\u5316\u4e00\u500b\u985e\u6642\uff0c\u6700\u5148\u88ab\u8abf\u7528\u7684\u65b9\u6cd5\u5176\u5be6\u662f __new__ \u65b9\u6cd5\u3002<\/p>\n
\u3000\u3000__new__<\/strong><\/p>\n
\u3000\u3000\u5176\u5be6__init__\u662f\u5728\u985e\u5be6\u4f8b\u88ab\u5275\u5efa\u4e4b\u5f8c\u8abf\u7528\u7684\uff0c\u5b83\u5b8c\u6210\u7684\u662f\u985e\u5be6\u4f8b\u7684\u521d\u59cb\u5316\u64cd\u4f5c\uff0c\u800c __new__\u65b9\u6cd5\u6b63\u662f\u5275\u5efa\u9019\u500b\u985e\u5be6\u4f8b\u7684\u65b9\u6cd5<\/p>\n
\u3000\u3000class Person: def __new__(cls, *args, **kwargs): print(‘\u8abf\u7528__new__\uff0c\u5275\u5efa\u985e\u5be6\u4f8b’) return super().__new__(Person) def __init__(self, name, age): print(‘\u8abf\u7528__init__\uff0c\u521d\u59cb\u5316\u5be6\u4f8b’) self.name = name self.age = age def __str__(self): return ‘‘.format(self.name, self.age)p1 = Person(‘\u5f35\u4e09’, 24)print(p1)<\/pre>\n
\u3000\u3000\u8f38\u51fa\uff1a<\/p>\n
\u3000\u3000\u8abf\u7528__new__\uff0c\u5275\u5efa\u985e\u5be6\u4f8b\u8abf\u7528__init__\uff0c\u521d\u59cb\u5316\u5be6\u4f8b<\/pre>\n
\u3000\u3000__new__\u65b9\u6cd5\u5728\u985e\u5b9a\u7fa9\u4e2d\u4e0d\u662f\u5fc5\u9808\u5beb\u7684\uff0c\u5982\u679c\u6c92\u5b9a\u7fa9\u7684\u8a71\u9ed8\u8a8d\u6703\u8abf\u7528object.__new__\u53bb\u5275\u5efa\u4e00\u500b\u5c0d\u8c61\uff08\u56e0\u70ba\u5275\u5efa\u985e\u7684\u6642\u5019\u9ed8\u8a8d\u7e7c\u627f\u7684\u5c31\u662fobject\uff09\u3002<\/p>\n
\u3000\u3000\u5982\u679c\u6211\u5011\u5728\u985e\u4e2d\u5b9a\u7fa9\u4e86__new__\u65b9\u6cd5\uff0c\u5c31\u662f\u91cd\u5beb\u4e86\u9ed8\u8a8d\u7684__new__\u65b9\u6cd5\uff0c\u6211\u5011\u53ef\u4ee5\u501f\u6b64\u81ea\u5b9a\u7fa9\u5275\u5efa\u5c0d\u8c61\u7684\u884c\u70ba\u3002<\/p>\n
\u3000\u3000\u8209\u500b\u4f8b\u5b50\uff1a<\/p>\n
\u3000\u3000\u91cd\u5beb\u985e\u7684__new__\u65b9\u6cd5\u4f86\u5be6\u73fe\u55ae\u4f8b\u6a21\u5f0f\u3002<\/p>\n
\u3000\u3000class Singleton: # \u91cd\u5beb__new__\u65b9\u6cd5\uff0c\u5be6\u73fe\u6bcf\u4e00\u6b21\u5be6\u4f8b\u5316\u7684\u6642\u5019\uff0c\u8fd4\u56de\u540c\u4e00\u500binstance\u5c0d\u8c61 def __new__(cls, *args, **kw): if not hasattr(cls, ‘_instance’): cls._instance = super().__new__(Singleton) return cls._instance def __init__(self, name, age): self.name = name self.age = ages1 = Singleton(‘\u5f35\u4e09’, 24)s2 = Singleton(‘\u674e\u56db’, 20)print(s1, s2) # \u9019\u5169\u5be6\u4f8b\u90fd\u4e00\u6a23print(s1.name, s2.name)<\/pre>\n
\u3000\u3000__call__<\/strong><\/p>\n
\u3000\u3000__call__ \u65b9\u6cd5\u7684\u57f7\u884c\u662f\u7531\u5c0d\u8c61\u5f8c\u52a0\u62ec\u865f\u89f8\u767c\u7684\uff0c\u5373\uff1a\u5c0d\u8c61()\u3002\u64c1\u6709\u6b64\u65b9\u6cd5\u7684\u5c0d\u8c61\u53ef\u4ee5\u50cf\u51fd\u6578\u4e00\u6a23\u88ab\u8abf\u7528\u3002<\/p>\n
\u3000\u3000class Person: def __init__(self, name, age): self.name = name self.age = age def __call__(self, *args, **kwargs): print(‘\u8abf\u7528\u5c0d\u8c61\u7684__call__\u65b9\u6cd5’)a = Person(‘\u5f35\u4e09’, 24) # \u985ePerson\u53ef\u8abf\u7528a() # \u5c0d\u8c61a\u53ef\u4ee5\u8abf\u7528<\/pre>\n
\u3000\u3000\u6ce8\u610f\uff1a<\/p>\n
\u3000\u3000__new__\u3001__init__\u3001__call__\u7b49\u65b9\u6cd5\u90fd\u4e0d\u662f\u5fc5\u9808\u5beb\u7684\u3002<\/p>\n
\u3000\u3000__doc__<\/strong><\/p>\n
\u3000\u3000\u5b9a\u7fa9\u985e\u7684\u63cf\u8ff0\u8cc7\u8a0a\u3002\u6ce8\u610f\u8a72\u8cc7\u8a0a\u7121\u6cd5\u88ab\u7e7c\u627f\u3002<\/p>\n
\u3000\u3000class A: “””\u6211\u662fA\u985e\u7684\u63cf\u8ff0\u8cc7\u8a0a””” passprint(A.__doc__)<\/pre>\n
\u3000\u3000__iter__\u548c__next__<\/strong><\/p>\n
\u3000\u3000\u5982\u679c\u4e00\u500b\u5c0d\u8c61\u64c1\u6709\u4e86__iter__\u548c__next__\u65b9\u6cd5\uff0c\u90a3\u9019\u500b\u5c0d\u8c61\u5c31\u662f\u53ef\u8fed\u4ee3\u5c0d\u8c61<\/p>\n
\u3000\u3000class A: def __init__(self, start, stop=None): if not stop: start, stop = 0, start self.start = start self.stop = stop def __iter__(self): return self def __next__(self): if self.start >= self.stop: raise StopIteration n = self.start self.start += 1 return na = A(1, 5)from collections import Iteratorprint(isinstance(a, Iterator))for i in A(1, 5): print(i)for i in A(5): print(i)aaa=A(1)print(next(aaa))print(next(aaa)) #\u62cb\u7570\u5e38<\/pre>\n
\u3000\u3000__enter__\u548c__exit__<\/strong><\/p>\n
\u3000\u3000\u4e00\u500b\u5c0d\u8c61\u5982\u679c\u5be6\u73fe\u4e86__enter__\u548c___exit__\u65b9\u6cd5\uff0c\u90a3\u9ebc\u9019\u500b\u5c0d\u8c61\u5c31\u652f\u6301\u4e0a\u4e0b\u6587\u7ba1\u7406\u5354\u8b70\uff0c\u5373with\u8a9e\u53e5<\/p>\n
\u3000\u3000class A: def __enter__(self): print(‘\u9032\u5165with\u8a9e\u53e5\u584a\u6642\u57f7\u884c\u6b64\u65b9\u6cd5\uff0c\u6b64\u65b9\u6cd5\u5982\u679c\u6709\u8fd4\u56de\u503c\u6703\u8ce6\u503c\u7d66as\u8072\u660e\u7684\u8b8a\u91cf’) return ‘oo’ def __exit__(self, exc_type, exc_val, exc_tb): print(‘\u9000\u51fawith\u4ee3\u78bc\u584a\u6642\u57f7\u884c\u6b64\u65b9\u6cd5’) print(‘1’, exc_type) print(‘2’, exc_val) print(‘3’, exc_tb)with A() as f: print(‘\u9032\u5165with\u8a9e\u53e5\u584a’) # with\u8a9e\u53e5\u4e2d\u4ee3\u78bc\u584a\u51fa\u73fe\u7570\u5e38\uff0c\u5247with\u5f8c\u7684\u4ee3\u78bc\u90fd\u7121\u6cd5\u57f7\u884c\u3002 # raise AttributeError(‘sb’) print(f) #f\u5217\u5370\u51faooprint(‘\u563f\u563f\u563f’)<\/pre>\n
\u3000\u3000\u4e0a\u4e0b\u6587\u7ba1\u7406\u5354\u8b70\u9069\u7528\u65bc\u90a3\u4e9b\u9032\u5165\u548c\u9000\u51fa\u4e4b\u5f8c\u81ea\u52d5\u57f7\u884c\u4e00\u4e9b\u4ee3\u78bc\u7684\u5834\u666f\uff0c\u4f8b\u5982\u6587\u4ef6\u3001\u7db2\u8def\u9023\u63a5\u3001\u8cc7\u6599\u5eab\u9023\u63a5\u6216\u4f7f\u7528\u9396\u7684\u7de8\u78bc\u5834\u666f\u7b49\u3002<\/p>\n
\u3000\u3000__len__<\/strong><\/p>\n
\u3000\u3000\u64c1\u6709__len__\u65b9\u6cd5\u7684\u5c0d\u8c61\u652f\u6301len(obj)\u64cd\u4f5c\u3002<\/p>\n
\u3000\u3000class A: def __init__(self): self.x = 1 self.y = 2 def __len__(self): return len(self.__dict__)a = A()print(len(a))<\/pre>\n
\u3000\u3000__hash__<\/strong><\/p>\n
\u3000\u3000\u64c1\u6709__hash__\u65b9\u6cd5\u7684\u5c0d\u8c61\u652f\u6301hash(obj)\u64cd\u4f5c\u3002<\/p>\n
\u3000\u3000class A: def __init__(self): self.x = 1 self.x = 2 def __hash__(self): return hash(str(self.x) + str(self.x))a = A()print(hash(a))<\/pre>\n
\u3000\u3000__eq__<\/strong><\/p>\n
\u3000\u3000\u64c1\u6709__eq__\u65b9\u6cd5\u7684\u5c0d\u8c61\u652f\u6301\u76f8\u7b49\u7684\u6bd4\u8f03\u64cd\u4f5c<\/p>\n
\u3000\u3000class A: def __init__(self,x,y): self.x = x self.y = y def __eq__(self,obj): # \u5217\u5370\u51fa\u6bd4\u8f03\u7684\u7b2c\u4e8c\u500b\u5c0d\u8c61\u7684x\u503c print(obj.x) if self.x +self.y == obj.x+obj.y: return True else: return Falsea = A(1,2)b = A(2,1)print(a == b)<\/pre><\/p>\n","protected":false},"excerpt":{"rendered":"