{"id":7438,"date":"2023-04-18T22:21:44","date_gmt":"2023-04-18T14:21:44","guid":{"rendered":"https:\/\/www.5x44.cn\/?p=7438"},"modified":"2023-04-20T11:57:03","modified_gmt":"2023-04-20T03:57:03","slug":"python%e4%b8%ad%e7%9a%84%e8%a3%85%e9%a5%b0%e5%99%a8%e8%af%ad%e6%b3%95decorator","status":"publish","type":"post","link":"https:\/\/www.5x44.cn\/?p=7438","title":{"rendered":"python\u4e2d\u7684\u88c5\u9970\u5668\u8bed\u6cd5[Decorator]"},"content":{"rendered":"\n

\u51fd\u6570\u88c5\u9970\u5668<\/h2>\n\n\n\n
\n
def decor_func(func):\n    def wrapper(x):\n        print(\"wrapper in\")\n        result = func(x)\n        print(\"wrapper out\")\n        return result\n    return wrapper\n\n@decor_func<\/strong><\/mark>\ndef do_something(x):\n    print(\"do something\")\n    return x * 2\n\nprint(do_something(3))<\/code><\/pre>\n\n\n\n
def decor_func(func):\n    def wrapper(*args, **kwargs):\n        print(\"wrapper in\")\n        result = func(*args, **kwargs)\n        print(\"wrapper out\")\n        return result\n    return wrapper\n\n\ndef do_something(x):\n    print(\"class method\")\n    return x * 2\n\ndo_something = decor_func(do_something)<\/mark><\/strong>\n\nprint(do_something(3))<\/code><\/pre>\n<\/div>\n\n\n\n
\u5de6\u53f3\u811a\u672c\u529f\u80fd\u76f8\u540c\uff0c\u5de6\u8fb9\u4f7f\u7528\u4e86\u88c5\u9970\u5668\u8bed\u6cd5\uff0c\u6267\u884c\u811a\u672c\u7684\u8f93\u51fa\uff1a<\/p>\n\n\n\n
wrapper in\ndo something\nwrapper out\n6<\/pre>\n\n\n\n
\u89e3\u91ca\u4e00\u4e0b\u53f3\u4fa7\u4ee3\u7801<\/h2>\n\n\n\n
    \n
  1. decor_func\u5c06do_something\u505a\u4e3a\u53c2\u6570\u4f20\u5165\uff0c\u5728decor_func\u5185\u90e8do_something\u7684\u51fd\u6570\u5165\u53e3\u5730\u5740\u6ca1\u53d8\uff0c\u53ea\u4e0d\u8fc7\u5b83\u73b0\u5728\u53ebfunc<\/strong>\u4e86\uff0c\u4e5f\u5c31\u662f\u6362\u4e86\u4e00\u4e2a\u540d\u5b57\u3002<\/li>\n\n\n\n
  2. decor_func\u5185\u90e8\u5b9a\u4e49\u4e86\u4e00\u4e2awrapper\u7684\u51fd\u6570\uff0c\u5e76\u8fd4\u56dewrapper\u51fd\u6570\u7684\u5165\u53e3\u5730\u5740\u505a\u4e3a\u51fd\u6570decor_func\u7684\u8fd4\u56de\u503c\uff0c\u5728dector_func\u5916\u90e8\uff0cwrapper\u53ebdo_something\uff0c\u540c\u6837\u662f\u6362\u4e86\u4e00\u540d\u5b57\uff0c\u5185\u90e8\u7684\u5165\u53e3\u5730\u5740\u8fd8\u662f\u6ca1\u53d8\u3002<\/li>\n\n\n\n
  3. \u6240\u5728\u5f53\u8c03\u7528do_something\u65f6\uff0c\u5b9e\u9645\u4e0a\u662f\u5728\u4f7f\u7528wrapper\u51fd\u6570\u3002<\/li>\n<\/ol>\n\n\n\n
    \u7c7b\u65b9\u6cd5\u7684\u88c5\u9970\u5668<\/h2>\n\n\n\n
    \u76f8\u6bd4\u51fd\u6570\u7684\u88c5\u9970\u5668\uff0c\u8fd9\u8981\u590d\u6742\u4e00\u4e9b\uff0c\u4e3b\u8981\u5206\u4e3a\u4e0b\u9762\u4e09\u6b65\uff1a<\/p>\n\n\n\n
    1. \u5b9a\u4e49\u7c7b\u548c\u65b9\u6cd5
    2. \u4f7f\u7528\u88c5\u9970\u5668\u201c\u88c5\u9970\u201d\u8be5\u65b9\u6cd5,\u88c5\u9970\u5668\u4f1a\u8fd4\u56de\u4e00\u4e2a\u66ff\u4ee3\u65b9\u6cd5
    3. \u5c06\u66ff\u4ee3\u65b9\u6cd5\u7ed1\u5b9a\u5230\u7c7b\u4e0a,\u66ff\u6362\u539f\u65b9\u6cd5<\/p>\n\n\n\n
    \n
    \n
    def decor_func(func):\n    def wrapper(*args, **kwargs):\n        print(\"wrapper in\")\n        result = func(*args, **kwargs)\n        print(\"wrapper out\")\n        return result\n    return wrapper\n\nclass Example:\n    def __init__(self, x=1):\n        self.val = x\n    @decor_func\n    def do_something(self):\n        print(\"class method\")\n        return self.val * 2\n\na= Example(2)\nprint(a.do_something())<\/code><\/pre>\n\n\n\n
    def decor_func(func):\n    def wrapper(*args, **kwargs):\n        print(\"wrapper in\")\n        result = func(*args, **kwargs)\n        print(\"wrapper out\")\n        return result\n    return wrapper\n\nclass Example:\n    def __init__(self,x=1):\n        self.val=x\n    def do_something(self):\n        print(\"class method\")\n        return self.val * 2\n\nExample.do_something = decor_func(Example.do_something)<\/mark><\/strong>\n\na=Example(2)\nprint(a.do_something())<\/code><\/pre>\n<\/div>\n<\/div>\n\n\n\n
    \u4e0a\u9762\u4e24\u6bb5\u4ee3\u7801\u529f\u80fd\u76f8\u540c\uff0c\u53f3\u8fb9\u7ea2\u8272\u90e8\u5206\u7b49\u540c\u4e8e\u5de6\u8fb9\u4f7f\u7528\u88c5\u9970\u5668\u8bed\u6cd5<\/mark><\/em>\uff0c\u5176\u8f93\u51fa\uff1a<\/p>\n\n\n\n
    wrapper in\nclass method\nwrapper out\n4<\/pre>\n\n\n\n
    PS:<\/mark><\/strong><\/p>\n\n\n\n
    \n
    \n
    \n
    *args\u8868\u793awrapper\u51fd\u6570\u53ef\u4ee5\u63a5\u6536\u4efb\u610f\u591a\u4e2a\u4f4d\u7f6e\u53c2\u6570,\u8fd9\u4e9b\u53c2\u6570\u4f1a\u88ab\u6536\u96c6\u5230\u4e00\u4e2a\u5143\u7ec4\u4e2d,\u540d\u4e3aargs\u3002<\/mark><\/p>\n\n\n\n
    **kwargs\u8868\u793awrapper\u51fd\u6570\u53ef\u4ee5\u63a5\u6536\u4efb\u610f\u591a\u4e2a\u5173\u952e\u5b57\u53c2\u6570,\u8fd9\u4e9b\u53c2\u6570\u4f1a\u88ab\u6536\u96c6\u5230\u4e00\u4e2a\u5b57\u5178\u4e2d,\u540d\u4e3akwargs\u3002<\/mark><\/p>\n\n\n\n
    \u8fd9\u4f7f\u5f97wrapper\u51fd\u6570\u53d8\u5f97\u975e\u5e38\u7075\u6d3b,\u53ef\u4ee5\u5904\u7406\u4efb\u610f\u53c2\u6570\u4f20\u9012\u7684\u60c5\u51b5\u3002\u5728\u88c5\u9970\u5668\u7684wrapper\u4e2d\u5c24\u5176\u6709\u7528,\u56e0\u4e3a\u5b83\u9700\u8981\u63a5\u53d7\u539f\u51fd\u6570func\u53ef\u80fd\u63a5\u6536\u7684\u4efb\u610f\u53c2\u6570\u3002<\/mark><\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
    \u7c7b\u7684\u88c5\u9970\u5668<\/h2>\n\n\n\n
    python\ndef count_objects(cls):\n    cls.num_instances = 0   \n    def new_init(self, *args, **kwargs):\n        cls.num_instances += 1  \n        cls.__init__(self, *args, **kwargs)  \n    cls.__init__ = new_init   \n    return cls  \n\n@count_objects  \nclass Example: \n    def __init__(self, name):\n        self.name = name<\/code><\/pre>\n\n\n\n
    \u7c7b\u7684\u88c5\u9970\u5668\u53ef\u4ee5\u7528\u4e8e\u4fee\u6539\u7c7b\uff0c\u5982\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u6211\u4eec\u5bf9Example\u7c7b\u6dfb\u52a0\u4e86\u4e00\u4e2a\u8ba1\u6570\u5668\u3002<\/p>\n\n\n\n
    \u5f53\u6211\u4eec\u4f7f\u7528@\u8bed\u6cd5\u5e94\u7528count_objects\u88c5\u9970\u5668\u65f6,\u4f1a\u53d1\u751f\u4ee5\u4e0b\u8fc7\u7a0b:<\/p>\n\n\n\n
    1. Example\u7c7b\u9996\u5148\u88ab\u5b9a\u4e49<\/p>\n\n\n\n
    2. count_objects\u51fd\u6570\u88ab\u8c03\u7528,\u5e76\u5c06Example<\/strong><\/mark>\u7c7b\u672c\u8eab\u505a\u4e3a\u53c2\u6570\u4f20\u5165cls<\/mark><\/strong>\uff0c\u8fd9\u65f6\u5728count_objects<\/mark><\/strong>\u51fd\u6570\u4e2dcls<\/mark><\/strong>\u5c31\u662fExample\u672c\u8eab\u3002<\/p>\n\n\n\n
    3. \u5728count_objects\u51fd\u6570\u5185,cls\u5f15\u7528\u7684\u5c31\u662fExample\u7c7b\u3002\u6211\u4eec\u5728\u51fd\u6570\u4e2d\u6dfb\u52a0\u4e86num_instances\u5c5e\u6027,\u5e76\u4fee\u6539\u4e86\u6784\u9020\u65b9\u6cd5,\u8fd9\u5b9e\u9645\u4e0a\u5c31\u662f\u5728\u4fee\u6539Example\u7c7b\u7684\u5b9a\u4e49\u3002<\/p>\n\n\n\n
    4. count_objects\u51fd\u6570\u8fd4\u56deExample\u7c7b,\u4e5f\u5c31\u662f\u5c06\u4fee\u6539\u540e\u7684Example\u7c7bDefinition\u8fd4\u56de<\/p>\n\n\n\n
    5. \u65b0\u8fd4\u56de\u7684Example\u7c7b\u5b9a\u4e49\u66ff\u4ee3\u4e86\u539f\u6765\u7684\u7c7b\u5b9a\u4e49,\u6210\u4e3a@count_objects\u4e4b\u540e\u7684Example\u7c7b\u7684\u5b9a\u4e49<\/p>\n\n\n\n
    6. \u6240\u4ee5,\u6700\u7ec8\u6211\u4eec\u5f97\u5230\u7684Example\u7c7b\u4e2d\u5305\u542b\u4e86count_objects\u51fd\u6570\u6dfb\u52a0\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\u53d8\u66f4<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u51fd\u6570\u88c5\u9970\u5668 \u5de6\u53f3\u811a\u672c\u529f\u80fd\u76f8\u540c\uff0c\u5de6\u8fb9\u4f7f\u7528\u4e86\u88c5\u9970\u5668\u8bed\u6cd5\uff0c\u6267\u884c\u811a\u672c\u7684\u8f93\u51fa\uff1a wrapper in do something wrapper out 6 \u89e3\u91ca\u4e00\u4e0b\u53f3\u4fa7\u4ee3…<\/p>\n
     Read More  Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-7438","post","type-post","status-publish","format-standard","hentry","category-python3"],"_links":{"self":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7438","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7438"}],"version-history":[{"count":6,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7438\/revisions"}],"predecessor-version":[{"id":7445,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7438\/revisions\/7445"}],"wp:attachment":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7438"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7438"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7438"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}