{"id":204032,"date":"2025-05-29T11:10:09","date_gmt":"2025-05-29T03:10:09","guid":{"rendered":"https:\/\/server.hk\/cnblog\/204032\/"},"modified":"2025-05-29T11:10:09","modified_gmt":"2025-05-29T03:10:09","slug":"python-%e5%b0%81%e8%a3%85%ef%bc%9a%e4%ba%86%e8%a7%a3%e7%a7%81%e6%9c%89%e6%88%90%e5%91%98%e5%92%8c%e5%8f%97%e4%bf%9d%e6%8a%a4%e6%88%90%e5%91%98","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/204032\/","title":{"rendered":"Python \u5c01\u88c5\uff1a\u4e86\u89e3\u79c1\u6709\u6210\u5458\u548c\u53d7\u4fdd\u62a4\u6210\u5458"},"content":{"rendered":"

<\/b> <\/p>\n

Python \u5c01\u88c5\uff1a\u4e86\u89e3\u79c1\u6709\u6210\u5458\u548c\u53d7\u4fdd\u62a4\u6210\u5458<\/h1>\n

\u76ee\u524d\u4e0a\u5df2\u7ecf\u6709\u5f88\u591a\u5173\u4e8e\u6587\u7ae0<\/span>\u7684\u6587\u7ae0\u4e86\uff0c\u81ea\u5df1\u5728\u521d\u6b21\u9605\u8bfb\u8fd9\u4e9b\u6587\u7ae0\u4e2d\uff0c\u4e5f\u89c1\u8bc6\u5230\u4e86\u5f88\u591a\u5b66\u4e60\u601d\u8def\uff1b\u90a3\u4e48\u672c\u6587\u300aPython \u5c01\u88c5\uff1a\u4e86\u89e3\u79c1\u6709\u6210\u5458\u548c\u53d7\u4fdd\u62a4\u6210\u5458\u300b<\/span>\uff0c\u4e5f\u5e0c\u671b\u80fd\u5e2e\u52a9\u5230\u5927\u5bb6\uff0c\u5982\u679c\u9605\u8bfb\u5b8c\u540e\u771f\u7684\u5bf9\u4f60\u5b66\u4e60\u6587\u7ae0<\/span>\u6709\u5e2e\u52a9\uff0c\u6b22\u8fce\u52a8\u52a8\u624b\u6307\uff0c\u8bc4\u8bba\u7559\u8a00\u5e76\u5206\u4eab~<\/p>\n

<\/p>\n

\u5728\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\uff08oop\uff09\u4e2d\uff0c\u5c01\u88c5<\/strong>\u662f\u4e00\u79cd\u5f3a\u5927\u7684\u6280\u672f\uff0c\u5b83\u5c06\u6570\u636e\uff08\u5c5e\u6027\uff09\u548c\u64cd\u4f5c\u5b83\u4eec\u7684\u51fd\u6570\uff08\u65b9\u6cd5\uff09\u7ed1\u5b9a\u5728\u4e00\u8d77\uff0c\u9650\u5236\u5bf9\u67d0\u4e9b\u7ec6\u8282\u7684\u8bbf\u95ee\u3002\u5c01\u88c5\u53ef\u4ee5\u9632\u6b62\u76f4\u63a5\u8bbf\u95ee\u5bf9\u8c61\u7684\u5185\u90e8\u72b6\u6001\uff0c\u5e76\u5141\u8bb8\u901a\u8fc7\u660e\u786e\u5b9a\u4e49\u7684\u63a5\u53e3\u8fdb\u884c\u53d7\u63a7\u4ea4\u4e92\u3002\u5728 python \u4e2d\uff0c\u8fd9\u662f\u901a\u8fc7\u4f7f\u7528 private<\/strong> \u548c protected<\/strong> \u6210\u5458\u6765\u5b9e\u73b0\u7684\uff0c\u5b83\u4eec\u662f\u7ef4\u62a4\u5bf9\u8c61\u5185\u90e8\u548c\u5916\u90e8\u63a5\u53e3\u4e4b\u95f4\u6e05\u6670\u8fb9\u754c\u7684\u91cd\u8981\u5de5\u5177\u3002<\/p>\n

\u672c\u6587\u6df1\u5165\u63a2\u8ba8\u4e86 python \u5c01\u88c5\uff0c\u91cd\u70b9\u5173\u6ce8\u79c1\u6709\u6210\u5458\u548c\u53d7\u4fdd\u62a4\u6210\u5458\u3001\u5b83\u4eec\u7684\u5de5\u4f5c\u65b9\u5f0f\u4ee5\u53ca\u5b9e\u9645\u7528\u9014\u3002<\/p>\n

\u5c01\u88c5\u53ef\u786e\u4fdd\u5bf9\u8c61\u7684\u6570\u636e\u9690\u85cf\u8d77\u6765\uff0c\u514d\u53d7\u5916\u90e8\u5e72\u6270\u548c\u8bef\u7528\u3002\u5b83\u901a\u8fc7\u9650\u5236\u5bf9\u7c7b\u4e2d\u67d0\u4e9b\u5c5e\u6027\u548c\u65b9\u6cd5\u7684\u8bbf\u95ee\u6765\u5141\u8bb8\u6570\u636e\u9690\u85cf\uff0c\u4ece\u800c\u786e\u4fdd\u6570\u636e\u5b8c\u6574\u6027\u3002\u8fd9\u5bf9\u4e8e\u6784\u5efa\u6a21\u5757\u5316\u548c\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u4e3a\u5b83\u5f3a\u5236\u6267\u884c\u6e05\u6670\u7684\u63a5\u53e3\u6765\u4e0e\u5bf9\u8c61\u7684\u5185\u90e8\u72b6\u6001\u8fdb\u884c\u4ea4\u4e92\u3002<\/p>\n

\u4e0e\u5176\u4ed6\u4e00\u4e9b\u7f16\u7a0b\u8bed\u8a00\u4e0d\u540c\uff0cpython \u6ca1\u6709\u4e25\u683c\u7684\u8bbf\u95ee\u4fee\u9970\u7b26\uff0c\u4f8b\u5982 private\u3001protected \u6216 public\u3002\u76f8\u53cd\uff0c\u5b83\u4f9d\u8d56\u547d\u540d\u7ea6\u5b9a\u548c\u67d0\u4e9b\u673a\u5236\u6765\u63a7\u5236\u5bf9\u5bf9\u8c61\u6210\u5458\u7684\u8bbf\u95ee\u3002<\/p>\n

\u79c1\u6709\u6210\u5458\u662f\u5728\u5b9a\u4e49\u5b83\u4eec\u7684\u7c7b\u4e4b\u5916\u65e0\u6cd5\u8bbf\u95ee\u7684\u5c5e\u6027\u6216\u65b9\u6cd5\u3002\u5728 python \u4e2d\uff0c\u79c1\u6709\u6210\u5458\u662f\u901a\u8fc7\u5728\u540d\u79f0\u524d\u6dfb\u52a0 \u53cc\u4e0b\u5212\u7ebf (__)<\/strong> \u6765\u521b\u5efa\u7684\u3002\u8fd9\u5411 python \u89e3\u91ca\u5668\u53d1\u51fa\u4fe1\u53f7\uff0c\u8868\u660e\u4e0d\u5e94\u4ece\u7c7b\u5916\u90e8\u76f4\u63a5\u8bbf\u95ee\u8fd9\u4e9b\u6210\u5458\uff0c\u8fd9\u79cd\u673a\u5236\u79f0\u4e3a name mangling<\/strong>.<\/p>\n

\u79c1\u4eba\u6210\u5458\u793a\u4f8b\uff1a <\/h4>\n
class bankaccount:\n    def __init__(self, balance):\n        self.__balance = balance  # private member\n\n    def deposit(self, amount):\n        if amount > 0:\n            self.__balance += amount\n            print(f\"deposited: {amount}\")\n\n    def withdraw(self, amount):\n        if 0 < amount <= self.__balance:\n            self.__balance -= amount\n            print(f\"withdrawn: {amount}\")\n        else:\n            print(\"insufficient funds\")\n\n    def get_balance(self):\n        return self.__balance  # public method to access private member\n\n# example usage\naccount = bankaccount(1000)\naccount.deposit(500)\naccount.withdraw(200)\nprint(\"current balance:\", account.get_balance())\n\n# trying to access the private member directly (will raise an attributeerror)\n# print(account.__balance)  # uncommenting this will cause an error\n<\/pre>\n
\u5728\u6b64\u793a\u4f8b\u4e2d\uff0cbankaccount \u7c7b\u6709\u4e00\u4e2a\u79c1\u6709\u5c5e\u6027 __balance\u3002 python \u6267\u884c\u7684\u540d\u79f0\u4fee\u6539\u5728\u5185\u90e8\u5c06 __balance \u66f4\u6539\u4e3a _bankaccount__balance\uff0c\u4f7f\u5f97\u4ece\u7c7b\u5916\u90e8\u8bbf\u95ee\u53d8\u5f97\u56f0\u96be\u3002\u8fd9\u53ef\u4ee5\u4fdd\u62a4\u5e10\u6237\u4f59\u989d\u4e0d\u88ab\u5916\u90e8\u4ee3\u7801\u76f4\u63a5\u4fee\u6539\u3002<\/p>\n
\u516c\u5171\u65b9\u6cd5<\/strong> deposit\u3001without \u548c get_balance \u5141\u8bb8\u4e0e\u79c1\u6709\u6210\u5458\u8fdb\u884c\u53d7\u63a7\u4ea4\u4e92\uff0c\u786e\u4fdd\u5bf9\u8c61\u7684\u72b6\u6001\u4ec5\u4ee5\u660e\u786e\u5b9a\u4e49\u7684\u65b9\u5f0f\u4fee\u6539\u3002<\/p>\n
 \u8981\u70b9\uff1a <\/h4>\n
    \n
  • \u79c1\u4eba\u6210\u5458\u4ee5 __ \u4e3a\u524d\u7f00\u3002<\/li>\n
  • \u65e0\u6cd5\u4ece\u73ed\u7ea7\u5916\u90e8\u76f4\u63a5\u8bbf\u95ee\u5b83\u4eec\u3002<\/li>\n
  • \u5b83\u4eec\u901a\u8fc7\u516c\u5171\u65b9\u6cd5\u8bbf\u95ee\uff0c\u5f3a\u5236\u5c01\u88c5\u3002<\/li>\n<\/ul>\n
    \u53d7\u4fdd\u62a4\u7684\u6210\u5458\u5e94\u8be5\u5728\u7c7b\u53ca\u5176\u5b50\u7c7b\u4e2d\u8bbf\u95ee\u3002\u5728 python \u4e2d\uff0c\u53d7\u4fdd\u62a4\u6210\u5458\u662f\u901a\u8fc7\u5728\u540d\u79f0\u524d\u6dfb\u52a0  \u5355\u4e0b\u5212\u7ebf (_)<\/strong> \u6765\u521b\u5efa\u7684\u3002\u8fd9\u5411\u5f00\u53d1\u4eba\u5458\u53d1\u51fa\u4fe1\u53f7\uff0c\u8868\u660e\u8fd9\u4e9b\u6210\u5458\u4ec5\u4f9b\u5185\u90e8\u4f7f\u7528\uff0c\u4f46\u5982\u6709\u5fc5\u8981\uff0c\u4ecd\u7136\u53ef\u4ee5\u4ece\u7c7b\u5916\u90e8\u8bbf\u95ee\u3002<\/p>\n
     \u53d7\u4fdd\u62a4\u6210\u5458\u793a\u4f8b\uff1a <\/h4>\n
    class Animal:\n    def __init__(self, name):\n        self._name = name  # Protected member\n\n    def speak(self):\n        raise NotImplementedError(\"Subclasses must implement this method\")\n\nclass Dog(Animal):\n    def speak(self):\n        return f\"{self._name} says Woof!\"\n\nclass Cat(Animal):\n    def speak(self):\n        return f\"{self._name} says Meow!\"\n\n# Example usage\ndog = Dog(\"Buddy\")\ncat = Cat(\"Whiskers\")\nprint(dog.speak())  # Output: Buddy says Woof!\nprint(cat.speak())  # Output: Whiskers says Meow!\n\n# Accessing a protected member (allowed, but not recommended)\nprint(dog._name)  # Output: Buddy\n<\/pre>\n
    \u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0canimal\u7c7b\u5b9a\u4e49\u4e86\u4e00\u4e2a\u53d7\u4fdd\u62a4\u7684\u6210\u5458_name\uff0c\u5b83\u53ef\u4ee5\u88ab\u5b50\u7c7b\uff08dog\u548ccat\uff09\u8bbf\u95ee\u3002\u5c3d\u7ba1 python \u5141\u8bb8\u4ece\u7c7b\u5916\u90e8\u8bbf\u95ee _name\uff0c\u4f46\u901a\u5e38\u4e0d\u9f13\u52b1\u8fd9\u6837\u505a\uff0c\u5982\u5355\u4e0b\u5212\u7ebf\u524d\u7f00\u6240\u793a\u3002<\/p>\n
     \u8981\u70b9\uff1a <\/h4>\n
      \n
    • \u53d7\u4fdd\u62a4\u7684\u6210\u5458\u4ee5 _ \u4e3a\u524d\u7f00\u3002<\/li>\n
    • \u53ef\u4ee5\u5728\u7c7b\u53ca\u5176\u5b50\u7c7b\u4e2d\u8bbf\u95ee\u5b83\u4eec\u3002<\/li>\n
    • \u6280\u672f\u4e0a\u5141\u8bb8\u5916\u90e8\u8bbf\u95ee\uff0c\u4f46\u4f5c\u4e3a\u6700\u4f73\u5b9e\u8df5\uff0c\u4e0d\u9f13\u52b1\u5916\u90e8\u8bbf\u95ee\u3002<\/li>\n<\/ul>\n\n\n\n\n\n\n\n\n
      aspect<\/th>\nprivate members<\/th>\nprotected members<\/th>\n<\/tr>\n<\/thead>\n
      syntax<\/td>\nprefix with __ (double underscore)<\/td>\nprefix with _ (single underscore)<\/td>\n<\/tr>\n
      access from outside class<\/td>\nnot allowed (name mangling used)<\/td>\nallowed but discouraged (by convention)<\/td>\n<\/tr>\n
      access in subclasses<\/td>\nnot allowed directly<\/td>\nallowed in subclasses<\/td>\n<\/tr>\n
      purpose<\/td>\nstrict data hiding for sensitive members<\/td>\nmeant for internal use but less restrictive<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
      \u5c01\u88c5\u53ef\u4ee5\u5b9e\u73b0\u6570\u636e\u9690\u85cf\uff0c\u4ece\u800c\u786e\u4fdd\u5173\u952e\u5c5e\u6027\u548c\u65b9\u6cd5\u4e0d\u4f1a\u88ab\u610f\u5916\u4fee\u6539\u6216\u8bbf\u95ee\u3002\u901a\u8fc7\u63a7\u5236\u5bf9\u5185\u90e8\u6570\u636e\u7684\u8bbf\u95ee\uff0c\u5c01\u88c5\uff1a<\/p>\n
        \n
      •  \u4fdd\u62a4\u5bf9\u8c61\u7684\u72b6\u6001<\/strong>\uff1a\u53ea\u80fd\u901a\u8fc7\u660e\u786e\u5b9a\u4e49\u7684\u65b9\u6cd5\u4fee\u6539\u5185\u90e8\u6570\u636e\uff0c\u964d\u4f4e\u9519\u8bef\u98ce\u9669\u5e76\u4fdd\u6301\u5bf9\u8c61\u5b8c\u6574\u6027\u3002<\/li>\n
      •  \u63d0\u9ad8\u53ef\u7ef4\u62a4\u6027<\/strong>\uff1a\u53ea\u8981\u5916\u90e8\u63a5\u53e3\u4fdd\u6301\u4e00\u81f4\uff0c\u7c7b\u7684\u5185\u90e8\u5de5\u4f5c\u65b9\u5f0f\u5c31\u53ef\u4ee5\u6539\u53d8\uff0c\u800c\u4e0d\u4f1a\u5f71\u54cd\u7a0b\u5e8f\u7684\u5176\u4ed6\u90e8\u5206\u3002<\/li>\n
      •  \u589e\u5f3a\u5b89\u5168\u6027<\/strong>\uff1a\u53ef\u4ee5\u5c4f\u853d\u654f\u611f\u4fe1\u606f\u6216\u529f\u80fd\u514d\u906d\u5916\u90e8\u7be1\u6539\u3002<\/li>\n<\/ul>\n
          \n
        1.  \u5bf9\u654f\u611f\u6570\u636e\u4f7f\u7528\u79c1\u6709\u6210\u5458<\/strong>\uff1a\u5982\u679c\u67d0\u4e9b\u5c5e\u6027\u6216\u65b9\u6cd5\u4e0d\u5e94\u88ab\u7a0b\u5e8f\u7684\u5176\u4ed6\u90e8\u5206\u76f4\u63a5\u66f4\u6539\uff0c\u8bf7\u5c06\u5b83\u4eec\u58f0\u660e\u4e3a\u79c1\u6709\u3002\u8fd9\u4f1a\u5f3a\u5236\u6267\u884c\u66f4\u5f3a\u7684\u5c01\u88c5\u3002<\/li>\n
        2.  \u5229\u7528\u53d7\u4fdd\u62a4\u7684\u6210\u5458\u8fdb\u884c\u7ee7\u627f<\/strong>\uff1a\u5728\u8bbe\u8ba1\u7ee7\u627f\u7c7b\u65f6\uff0c\u4f7f\u7528\u53d7\u4fdd\u62a4\u7684\u6210\u5458\u6765\u8868\u660e\u67d0\u4e9b\u5c5e\u6027\u6216\u65b9\u6cd5\u4f9b\u5b50\u7c7b\u4f7f\u7528\u3002<\/li>\n
        3.  \u516c\u5f00\u516c\u5171\u65b9\u6cd5<\/strong>\uff1a\u63d0\u4f9b\u5c01\u88c5\u5185\u90e8\u884c\u4e3a\u7684\u5b9a\u4e49\u826f\u597d\u7684\u516c\u5171\u65b9\u6cd5\uff08getter\u3001setter \u6216\u4e1a\u52a1\u903b\u8f91\u65b9\u6cd5\uff09\uff0c\u800c\u4e0d\u662f\u5141\u8bb8\u76f4\u63a5\u8bbf\u95ee\u5185\u90e8\u6570\u636e\u3002<\/li>\n
        4.  \u9075\u5faa\u547d\u540d\u7ea6\u5b9a<\/strong>\uff1a\u867d\u7136 python \u4e0d\u5f3a\u5236\u6267\u884c\u4e25\u683c\u7684\u8bbf\u95ee\u63a7\u5236\uff0c\u4f46\u9075\u5faa\u79c1\u6709 (__) \u548c\u53d7\u4fdd\u62a4 (_) \u6210\u5458\u7684\u7ea6\u5b9a\u53ef\u786e\u4fdd\u60a8\u7684\u4ee3\u7801\u53ef\u8bfb\u4e14\u53ef\u7ef4\u62a4\u3002<\/li>\n<\/ol>\n
          \u5c01\u88c5\u662fpython\u9762\u5411\u5bf9\u8c61\u8303\u4f8b\u7684\u4e00\u4e2a\u91cd\u8981\u65b9\u9762\uff0c\u63d0\u4f9b\u4e86\u4e00\u79cd\u9690\u85cf\u5185\u90e8\u6570\u636e\u5e76\u63a7\u5236\u5916\u90e8\u4ee3\u7801\u4e0e\u5bf9\u8c61\u4ea4\u4e92\u65b9\u5f0f\u7684\u65b9\u6cd5\u3002\u901a\u8fc7\u79c1\u6709\u548c\u53d7\u4fdd\u62a4\u7684\u6210\u5458\uff0cpython \u5f00\u53d1\u4eba\u5458\u53ef\u4ee5\u6784\u5efa\u4ee3\u7801\u4ee5\u9632\u6b62\u672a\u7ecf\u6388\u6743\u7684\u8bbf\u95ee\uff0c\u5e76\u4f7f\u5bf9\u8c61\u66f4\u52a0\u6a21\u5757\u5316\u3001\u5065\u58ee\u548c\u5b89\u5168\u3002<\/p>\n
          \u901a\u8fc7\u7406\u89e3\u5e76\u6b63\u786e\u4f7f\u7528\u79c1\u6709\u6210\u5458\u548c\u53d7\u4fdd\u62a4\u6210\u5458\uff0c\u60a8\u53ef\u4ee5\u521b\u5efa\u4fdd\u62a4\u5176\u5185\u90e8\u72b6\u6001\u7684\u7c7b\uff0c\u540c\u65f6\u63d0\u4f9b\u6e05\u6670\u4e14\u53d7\u63a7\u7684\u4ea4\u4e92\u63a5\u53e3\u3002\u8fd9\u63d0\u9ad8\u4e86\u4ee3\u7801\u7684\u53ef\u7ef4\u62a4\u6027\u548c\u53ef\u9760\u6027\uff0c\u4ece\u957f\u8fdc\u6765\u770b\uff0c\u4f7f\u60a8\u7684\u7a0b\u5e8f\u66f4\u5177\u9002\u5e94\u6027\u548c\u66f4\u6613\u4e8e\u4f7f\u7528\u3002<\/p>\n
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