{"id":112041,"date":"2020-05-31T03:42:27","date_gmt":"2020-05-30T19:42:27","guid":{"rendered":"http:\/\/4563.org\/?p=112041"},"modified":"2020-05-31T03:42:27","modified_gmt":"2020-05-30T19:42:27","slug":"python-%e5%a6%82%e4%bd%95%e5%ae%9e%e7%8e%b0%e4%b8%80%e4%b8%aa%e5%92%8c%e5%b1%9e%e6%80%a7%e5%80%bc%e7%9b%b8%e5%85%b3%e7%9a%84%e5%8d%95%e4%be%8b%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=112041","title":{"rendered":"Python \u5982\u4f55\u5b9e\u73b0\u4e00\u4e2a\u548c\u5c5e\u6027\u503c\u76f8\u5173\u7684\u5355\u4f8b\uff1f"},"content":{"rendered":"
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Python \u5982\u4f55\u5b9e\u73b0\u4e00\u4e2a\u548c\u5c5e\u6027\u503c\u76f8\u5173\u7684\u5355\u4f8b\uff1f <\/h1>\n

<\/p>\n

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\u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span> <\/i> 3<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n

\u5047\u5982\u67d0\u4e2a\u7c7b\u7684\u5b9e\u4f8b\u6bd4\u8f83\u8017\u8d39\u5185\u5b58\u6216\u8005\u5b9e\u4f8b\u5316\u7684\u65f6\u5019\u8017\u8d39\u8f83\u591a\u7684\u65f6\u95f4\uff0c\u56e0\u6b64\u60f3\u5b9e\u73b0\u4e00\u4e2a\u548c\u5b9e\u4f8b\u5c5e\u6027\u76f8\u5173\u7684\u5355\u4f8b\uff0c\u4e0d\u77e5\u9053\u8fd9\u4e48\u53eb\u5bf9\u4e0d\u5bf9\uff0c\uff0c\uff0c\u60f3\u8fbe\u5230\u7684\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n

class Example():     def __init__(self, attr1=None, attr2=None):         self.attr1 = attr1         self.attr2 = attr2  instance1 = Example('attr1', 'attr2') instance2 = Example('attr1', 'attr2') instance3 = Example('attr3', 'attr4') instance4 = Example('attr1', 'attr3')  # \u5e0c\u671b\u8fbe\u5230\u7684\u6548\u679c # instance1 is instance2 \u7ed3\u679c\u4e3a True # instance1 is instance3 \u7ed3\u679c\u4e3a False # instance1 is instance4 \u7ed3\u679c\u4e3a False <\/code><\/pre>\n
\u6216\u8005\u6709\u4ec0\u4e48\u5176\u4ed6\u66f4\u597d\u7684\u89e3\u51b3\u65b9\u6cd5<\/p>\n<\/p><\/div>\n
 \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (14<\/span>)        <\/div>\n
 <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : ruanimal <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u641e\u4e2a\u5b57\u5178\u505a cache \u5c31 ok \u4e86\u554a                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @ruanimal \u5982\u679c\u5c5e\u6027\u503c\u8f83\u591a\u90a3\u8fd9\u4e2a\u5b57\u5178\u53ef\u80fd\u6709\u597d\u591a\u5c42\u5427\uff0c\uff0c\uff0c\uff0c\uff0c\u800c\u4e14\u6709\u597d\u51e0\u4e2a\u8fd9\u6837\u7684\u7c7b\u4ed6\u4eec\u5c5e\u6027\u4e0d\u540c\u5c31\u8981\u5199\u4e0d\u540c\u7684\u4ee3\u7801\u548c\u5b57\u5178\uff0c\u6240\u4ee5\u6709\u4e86\u8fd9\u4e2a\u60f3\u6cd5                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : a719114136 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u91cd\u5199 __eq__()\u65b9\u6cd5\uff0c\u7136\u540e\u7528 == \u5224\u65ad                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : ClericPy <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 Borg \u6a21\u5f0f? \u7f13\u5b58\u5b57\u5178\u653e\u5230\u7c7b\u5c5e\u6027\u91cc, \u5728 `__new__` \u91cc\u505a\u7c7b\u4f3c\u5355\u4f8b\u7684\u4e8b\u60c5                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : ClericPy <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u7ea0\u6b63\u4e0b #4<\/p>\n
    \u540e\u534a\u53e5\u8bf4\u7684\u662f\u5355\u4f8b\u6a21\u5f0f… new \u91cc\u505a\u7684\u5c31\u662f\u7528\u5143\u7ec4 (attr1, attr2) \u505a key \u53bb\u7f13\u5b58\u91cc\u627e<\/p>\n
    \u4e0a\u534a\u53e5\u662f\u8bf4\u53ef\u4ee5\u53c2\u8003\u4e0b Borg \u6a21\u5f0f                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : cassidyhere <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4f60\u9700\u8981\u521b\u5efa\u7f13\u5b58\u5b9e\u4f8b
    python cookbook \u91cc\u7684\u4f8b\u5b50\uff1a<\/p>\n
    import weakref<\/p>\n
    class Cached(type):
     def __init__(self, *args, **kwargs):
     super().__init__(*args, **kwargs)
     self.__cache = weakref.WeakValueDictionary()<\/p>\n
     def __call__(self, *args):
     if args in self.__cache:
     return self.__cache[args]
     else:
     obj = super().__call__(*args)
     self.__cache[args] = obj
     return obj<\/p>\n
    # Example
    class Spam(metaclass=Cached):
     def __init__(self, name):
     self.name = name<\/p>\n
    >>> a = Spam(‘Guido’)
    >>> b = Spam(‘Diana’)
    >>> c = Spam(‘Guido’) # Cached
    >>> a is b
    False
    >>> a is c # Cached value returned
    True                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : islxyqwe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 “`python3
    from functools import lru_cache
    @lru_cache(None)
    class Example():
     def __init__(self, attr1=None, attr2=None):
     self.attr1 = attr1
     self.attr2 = attr2<\/p>\n
    instance1 = Example(‘attr1’, ‘attr2’)
    instance2 = Example(‘attr1’, ‘attr2’)
    instance3 = Example(‘attr3’, ‘attr4’)
    instance4 = Example(‘attr1’, ‘attr3’)
    print(instance1 is instance2,instance1 is instance3,instance1 is instance4)
    “`
    \u7ed3\u679c\uff1aTrue False False                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : Vegetable <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e0a\u6b63\u89e3,\u76f4\u63a5 lru_cache \u5b8c\u7f8e\u7b26\u5408\u4f60\u7684\u9700\u6c42,\u540c\u6837\u5165\u53c2\u7684\u8c03\u7528\u4f1a\u88ab\u7f13\u5b58                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @islxyqwe nice                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @islxyqwe \u5f53\u6709\u9ed8\u8ba4\u53c2\u6570\u7684\u65f6\u5019\u6709\u70b9\u5c0f\u95ee\u9898\uff0c\u4ed6\u662f\u6839\u636e\u4f20\u5165\u53c2\u6570\u6765\u51b3\u5b9a\u7684                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : noparking188 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u5982\u679c\u662f\u6570\u636e\u76f8\u5173\u7684\u8bdd\uff0c\u6216\u8bb8\u53ef\u4ee5\u7528\u4e0b dataclasses                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : ruanimal <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @huazhaozhe \u5b57\u5178\u53ef\u4ee5\u7528 tuple \u505a key\uff0c\u8fd9\u6837\u591a\u5c11\u4e2a\u5c5e\u6027\u90fd\u53ef\u4ee5\u3002 \u5982\u679c\u4f7f\u7528\u5355\u4f8b\uff0c\u6700\u7ec8\u4e5f\u662f\u7528 dict \u6765\u7f13\u5b58\u7684\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @ruanimal \u8fd9\u6837\u7684\u8bdd\u4f20\u5165\u53c2\u6570\u5fc5\u987b\u4e00\u6837\u7684\u987a\u5e8f\uff0c\u5426\u5219\u5c31\u4e0d\u662f\u540c\u4e00\u4e2a tuple                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : huazhaozhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @ruanimal \u800c\u4e14\u5f53\u6709\u9ed8\u8ba4\u53c2\u6570\u65f6\u4e5f\u6709\u70b9\u95ee\u9898\uff0c\u4e0d\u8fc7\u4e5f\u53ef\u4ee5\u7528\u4e86\uff0c\u4e0a\u8fb9\u6709\u4eba\u8bf4\u7684 lru_cache \u53ef\u4ee5\u76f4\u63a5\u7528                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"
    Python \u5982\u4f55\u5b9e\u73b0\u4e00\u4e2a\u548c\u5c5e\u6027\u503c…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/112041"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=112041"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/112041\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=112041"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=112041"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=112041"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}