{"id":134230,"date":"2020-07-07T01:19:56","date_gmt":"2020-07-06T17:19:56","guid":{"rendered":"http:\/\/4563.org\/?p=134230"},"modified":"2020-07-07T01:19:56","modified_gmt":"2020-07-06T17:19:56","slug":"python-%e4%b8%ba%e4%bb%80%e4%b9%88%e5%8f%aa%e9%9c%80%e4%b8%80%e6%9d%a1%e8%af%ad%e5%8f%a5abba%ef%bc%8c%e5%b0%b1%e8%83%bd%e7%9b%b4%e6%8e%a5%e4%ba%a4%e6%8d%a2%e4%b8%a4%e4%b8%aa","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=134230","title":{"rendered":"Python \u4e3a\u4ec0\u4e48\u53ea\u9700\u4e00\u6761\u8bed\u53e5\u201ca,b=b,a\u201d\uff0c\u5c31\u80fd\u76f4\u63a5\u4ea4\u6362\u4e24\u4e2a\u53d8\u91cf\uff1f"},"content":{"rendered":"
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Python \u4e3a\u4ec0\u4e48\u53ea\u9700\u4e00\u6761\u8bed\u53e5\u201ca,b=b,a\u201d\uff0c\u5c31\u80fd\u76f4\u63a5\u4ea4\u6362\u4e24\u4e2a\u53d8\u91cf\uff1f <\/h1>\n

<\/p>\n

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\u8cc7\u6df1\u5927\u4f6c : chinesehuazhou <\/span> <\/i> 7<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n

\u5206\u4eab\u4e00\u7bc7\u6587\u7ae0\uff1a<\/p>\n

\u4ece\u63a5\u89e6 Python \u65f6\u8d77\uff0c\u6211\u5c31\u89c9\u5f97 Python \u7684\u5143\u7ec4\u89e3\u5305\uff08 unpacking \uff09\u633a\u6709\u610f\u601d\uff0c\u975e\u5e38\u7b80\u6d01\u597d\u7528\u3002<\/p>\n

\u6700\u663e\u800c\u6613\u89c1\u7684\u4f8b\u5b50\u5c31\u662f\u591a\u91cd\u8d4b\u503c\uff0c\u5373\u5728\u4e00\u6761\u8bed\u53e5\u4e2d\u540c\u65f6\u7ed9\u591a\u4e2a\u53d8\u91cf\u8d4b\u503c\uff1a<\/p>\n

>>> x, y = 1, 2 >>> print(x, y)  # \u7ed3\u679c\uff1a1 2 <\/code><\/pre>\n
\u5728\u6b64\u4f8b\u4e2d\uff0c\u8d4b\u503c\u64cd\u4f5c\u7b26\u201c=\u201d\u53f7\u7684\u53f3\u4fa7\u7684\u4e24\u4e2a\u6570\u5b57\u4f1a\u88ab\u5b58\u5165\u5230\u4e00\u4e2a\u5143\u7ec4\u4e2d\uff0c\u5373\u53d8\u6210 (1,2)\uff0c\u7136\u540e\u518d\u88ab\u89e3\u5305\uff0c\u4f9d\u6b21\u8d4b\u503c\u7ed9\u201c=\u201d\u53f7\u5de6\u4fa7\u7684\u4e24\u4e2a\u53d8\u91cf\u3002<\/p>\n
\u5982\u679c\u6211\u4eec\u76f4\u63a5\u5199x = 1,2<\/code> \uff0c\u7136\u540e\u6253\u5370\u51fa x\uff0c\u6216\u8005\u5728\u201c=\u201d\u53f7\u53f3\u4fa7\u5199\u6210\u4e00\u4e2a\u5143\u7ec4\uff0c\u5c31\u80fd\u8bc1\u5b9e\u5230\u8fd9\u4e00\u70b9\uff1a<\/p>\n
>>> x = 1, 2 >>> print(x)     # \u7ed3\u679c\uff1a(1, 2) >>> x, y = (1, 2) >>> print(x, y)  # \u7ed3\u679c\uff1a1 2 <\/code><\/pre>\n
\u4e00\u4e9b\u535a\u5ba2\u6216\u516c\u4f17\u53f7\u6587\u7ae0\u5728\u4ecb\u7ecd\u5230\u8fd9\u4e2a\u7279\u6027\u65f6\uff0c\u901a\u5e38\u4f1a\u987a\u7740\u4e3e\u4e00\u4e2a\u4f8b\u5b50\uff0c\u5373\u57fa\u4e8e\u4e24\u4e2a\u53d8\u91cf\uff0c\u76f4\u63a5\u4ea4\u6362\u5b83\u4eec\u7684\u503c\uff1a<\/p>\n
>>> x, y = 1, 2 >>> x, y = y, x >>> print(x, y) # \u7ed3\u679c\uff1a2 1 <\/code><\/pre>\n
\u4e00\u822c\u800c\u8a00\uff0c\u4ea4\u6362\u4e24\u4e2a\u53d8\u91cf\u7684\u64cd\u4f5c\u9700\u8981\u5f15\u5165\u7b2c\u4e09\u4e2a\u53d8\u91cf\u3002\u9053\u7406\u5f88\u7b80\u5355\uff0c\u5982\u679c\u8981\u4ea4\u6362\u4e24\u4e2a\u676f\u5b50\u4e2d\u6240\u88c5\u7684\u6c34\uff0c\u81ea\u7136\u4f1a\u9700\u8981\u7b2c\u4e09\u4e2a\u5bb9\u5668\u4f5c\u4e3a\u4e2d\u8f6c\u3002<\/p>\n
\u7136\u800c\uff0cPython \u7684\u5199\u6cd5\u5e76\u4e0d\u9700\u8981\u501f\u52a9\u4e2d\u95f4\u53d8\u91cf\uff0c\u5b83\u7684\u5f62\u5f0f\u5c31\u8ddf\u524d\u9762\u7684\u89e3\u5305\u8d4b\u503c\u4e00\u6837\u3002\u6b63\u56e0\u4e3a\u8fd9\u4e2a\u5f62\u5f0f\u76f8\u4f3c\uff0c\u5f88\u591a\u4eba\u5c31\u8bef\u4ee5\u4e3a Python \u7684\u53d8\u91cf\u4ea4\u6362\u64cd\u4f5c\u4e5f\u662f\u57fa\u4e8e\u89e3\u5305\u64cd\u4f5c\u3002<\/p>\n
\u4f46\u662f\uff0c\u4e8b\u5b9e\u662f\u5426\u5982\u6b64\u5462\uff1f<\/p>\n
\u6211\u641c\u7d22\u4e86\u4e00\u756a\uff0c\u53d1\u73b0\u6709\u4eba\u8bd5\u56fe\u56de\u7b54\u8fc7\u8fd9\u4e2a\u95ee\u9898\uff0c\u4f46\u662f\u4ed6\u4eec\u7684\u56de\u7b54\u57fa\u672c\u4e0d\u591f\u5168\u9762\u3002\uff08\u5f53\u7136\uff0c\u6709\u4e0d\u5c11\u662f\u9519\u8bef\u7684\u7b54\u6848\uff0c\u8fd8\u6709\u66f4\u591a\u4eba\u53ea\u662f\u77e5\u5176\u7136\uff0c\u5374\u4ece\u672a\u60f3\u8fc7\u8981\u77e5\u5176\u6240\u4ee5\u7136\uff09<\/p>\n
\u5148\u628a\u672c\u6587\u7684\u7b54\u6848\u653e\u51fa\u6765\u5427\uff1aPython \u7684\u4ea4\u6362\u53d8\u91cf\u64cd\u4f5c\u4e0d\u5b8c\u5168\u57fa\u4e8e\u89e3\u5305\u64cd\u4f5c\uff0c\u6709\u65f6\u5019\u662f\uff0c\u6709\u65f6\u5019\u4e0d\u662f\uff01<\/strong><\/p>\n
\u6709\u6ca1\u6709\u89c9\u5f97\u8fd9\u4e2a\u7b54\u6848\u5f88\u795e\u5947\u5462\uff1f\u662f\u4e0d\u662f\u95fb\u6240\u672a\u95fb\uff1f\uff01<\/p>\n
\u5230\u5e95\u600e\u4e48\u56de\u4e8b\u5462\uff1f\u5148\u6765\u770b\u770b\u6807\u9898\u4e2d\u6700\u7b80\u5355\u7684\u4e24\u4e2a\u53d8\u91cf\u7684\u60c5\u51b5\uff0c\u6211\u4eec\u4e0adis<\/code> \u5927\u6740\u5668\u770b\u770b\u7f16\u8bd1\u7684\u5b57\u8282\u7801\uff1a<\/p>\n
\"Python<\/p>\n
\u4e0a\u56fe\u5f00\u4e86\u4e24\u4e2a\u7a97\u53e3\uff0c\u53ef\u4ee5\u65b9\u4fbf\u6bd4\u8f83\u201ca,b=b,a\u201d\u4e0e\u201ca,b=1,2\u201d\u7684\u4e0d\u540c\uff1a<\/p>\n
    \n
  • \u201ca,b=b,a\u201d\u64cd\u4f5c\uff1a\u4e24\u4e2a LOAD_FAST \u662f\u4ece\u5c40\u90e8\u4f5c\u7528\u57df\u4e2d\u8bfb\u53d6\u53d8\u91cf\u7684\u5f15\u7528\uff0c\u5e76\u5b58\u5165\u6808\u4e2d\uff0c\u63a5\u7740\u662f\u6700\u5173\u952e\u7684 ROT_TWO \u64cd\u4f5c\uff0c\u5b83\u4f1a\u4ea4\u6362\u4e24\u4e2a\u53d8\u91cf\u7684\u5f15\u7528\u503c\uff0c\u7136\u540e\u4e24\u4e2a STORE_FAST \u662f\u5c06\u6808\u4e2d\u7684\u53d8\u91cf\u5199\u5165\u5c40\u90e8\u4f5c\u7528\u57df\u4e2d\u3002<\/li>\n
  • \u201ca,b=1,2\u201d\u64cd\u4f5c\uff1a\u7b2c\u4e00\u6b65 LOAD_CONST \u628a\u201c=\u201d\u53f7\u53f3\u4fa7\u7684\u4e24\u4e2a\u6570\u5b57\u4f5c\u4e3a\u5143\u7ec4\u653e\u5230\u6808\u4e2d\uff0c\u7b2c\u4e8c\u6b65 UNPACK_SEQUENCE \u662f\u5e8f\u5217\u89e3\u5305\uff0c\u63a5\u7740\u628a\u89e3\u5305\u7ed3\u679c\u5199\u5165\u5c40\u90e8\u4f5c\u7528\u57df\u7684\u53d8\u91cf\u4e0a\u3002<\/li>\n<\/ul>\n
    \u5f88\u660e\u663e\uff0c\u5f62\u5f0f\u76f8\u4f3c\u7684\u4e24\u79cd\u5199\u6cd5\u5b9e\u9645\u4e0a\u5b8c\u6210\u7684\u64cd\u4f5c\u5e76\u4e0d\u76f8\u540c\u3002\u5728\u4ea4\u6362\u53d8\u91cf\u7684\u64cd\u4f5c\u4e2d\uff0c\u5e76\u6ca1\u6709\u88c5\u5305\u548c\u89e3\u5305\u7684\u6b65\u9aa4\uff01<\/p>\n
    ROT_TWO \u6307\u4ee4\u662f CPython \u89e3\u91ca\u5668\u5b9e\u73b0\u7684\u5bf9\u4e8e\u6808\u9876\u4e24\u4e2a\u5143\u7d20\u7684\u5feb\u6377\u64cd\u4f5c\uff0c\u6539\u53d8\u5b83\u4eec\u6307\u5411\u7684\u5f15\u7528\u5bf9\u8c61\u3002<\/p>\n
    \u8fd8\u6709\u4e24\u4e2a\u7c7b\u4f3c\u7684\u6307\u4ee4\u662f ROT_THREE \u548c ROT_FOUR\uff0c\u5206\u522b\u662f\u5feb\u6377\u4ea4\u6362\u4e09\u548c\u56db\u4e2a\u53d8\u91cf\uff08\u6458\u81ea\uff1aceval.c \u6587\u4ef6\uff0c\u6700\u65b0\u7684 3.9 \u5206\u652f\uff09\uff1a<\/p>\n
    \"Python<\/p>\n
    \u9884\u5b9a\u4e49\u7684\u6808\u9876\u64cd\u4f5c\u5982\u4e0b\uff1a<\/p>\n
    \"Python<\/p>\n
    \u67e5\u770b\u5b98\u65b9\u6587\u6863\u4e2d\u5bf9\u4e8e\u8fd9\u51e0\u4e2a\u6307\u4ee4\u7684\u89e3\u91ca\uff0c\u5176\u4e2d ROT_FOUR \u662f 3.8 \u7248\u672c\u65b0\u52a0\u7684\uff1a<\/p>\n
    \n
      \n
    • \n
      ROT_TWO<\/code><\/p>\n
      Swaps the two top-most stack items.<\/p>\n<\/li>\n
    • \n
      ROT_THREE<\/code><\/p>\n
      Lifts second and third stack item one position up, moves top down to position three.<\/p>\n<\/li>\n
    • \n
      ROT_FOUR<\/code><\/p>\n
      Lifts second, third and forth stack items one position up, moves top down to position four. New in version 3.8.<\/p>\n<\/li>\n<\/ul>\n<\/blockquote>\n
      CPython \u5e94\u8be5\u662f\u4ee5\u4e3a\u8fd9\u51e0\u79cd\u53d8\u91cf\u7684\u4ea4\u6362\u64cd\u4f5c\u5f88\u5e38\u89c1\uff0c\u56e0\u6b64\u624d\u63d0\u4f9b\u4e86\u4e13\u95e8\u7684\u4f18\u5316\u6307\u4ee4\u3002\u5c31\u50cf [-5,256] \u8fd9\u4e9b\u5c0f\u6574\u6570\u88ab\u9884\u5148\u653e\u5230\u4e86\u6574\u6570\u6c60\u91cc\u4e00\u6837\u3002<\/p>\n
      \u5bf9\u4e8e\u66f4\u591a\u53d8\u91cf\u7684\u4ea4\u6362\u64cd\u4f5c\uff0c\u5b9e\u9645\u4e0a\u5219\u4f1a\u7528\u5230\u524d\u9762\u8bf4\u7684\u89e3\u5305\u64cd\u4f5c\uff1a<\/p>\n
      \"Python<\/p>\n
      \u622a\u56fe\u4e2d\u7684 BUILD_TUPLE \u6307\u4ee4\u4f1a\u5c06\u7ed9\u5b9a\u6570\u91cf\u7684\u6808\u9876\u5143\u7d20\u521b\u5efa\u6210\u5143\u7ec4\uff0c\u7136\u540e\u88ab UNPACK_SEQUENCE \u6307\u4ee4\u89e3\u5305\uff0c\u518d\u4f9d\u6b21\u8d4b\u503c\u3002<\/p>\n
      \u503c\u5f97\u4e00\u63d0\u7684\u662f\uff0c\u6b64\u5904\u4e4b\u6240\u4ee5\u6bd4\u524d\u9762\u7684\u201ca,b=1,2\u201d\u591a\u51fa\u4e00\u4e2a build \u64cd\u4f5c\uff0c\u662f\u56e0\u4e3a\u6bcf\u4e2a\u53d8\u91cf\u7684 LOAD_FAST \u9700\u8981\u5148\u5355\u72ec\u5165\u6808\uff0c\u65e0\u6cd5\u76f4\u63a5\u88ab\u7ec4\u5408\u6210 LOAD_CONST \u5165\u6808\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u201c=\u201d\u53f7\u53f3\u4fa7\u6709\u53d8\u91cf\u65f6\uff0c\u4e0d\u4f1a\u51fa\u73b0\u524d\u6587\u4e2d\u7684 LOAD_CONST \u4e00\u4e2a\u5143\u7ec4\u7684\u60c5\u51b5\u3002<\/p>\n
      \u6700\u540e\u8fd8\u6709\u4e00\u4e2a\u503c\u5f97\u4e00\u63d0\u7684\u7ec6\u8282\uff0c\u90a3\u51e0\u4e2a\u6307\u4ee4\u662f\u8ddf\u6808\u4e2d\u5143\u7d20\u7684\u6570\u91cf\u6709\u5173\uff0c\u800c\u4e0d\u662f\u8ddf\u8d4b\u503c\u8bed\u53e5\u4e2d\u5b9e\u9645\u4ea4\u6362\u7684\u53d8\u91cf\u6570\u6709\u5173\u3002\u770b\u4e00\u4e2a\u4f8b\u5b50\u5c31\u660e\u767d\u4e86\uff1a<\/p>\n
      \"Python<\/p>\n
      \u5206\u6790\u81f3\u6b64\uff0c\u4f60\u5e94\u8be5\u660e\u767d\u524d\u6587\u4e2d\u7684\u7ed3\u8bba\u662f\u600e\u4e48\u56de\u4e8b\u4e86\u5427\uff1f<\/p>\n
      \u6211\u4eec\u7a0d\u5fae\u603b\u7ed3\u4e00\u4e0b\uff1a<\/p>\n
        \n
      • Python \u80fd\u5728\u4e00\u6761\u8bed\u53e5\u4e2d\u5b9e\u73b0\u591a\u91cd\u8d4b\u503c\uff0c\u8fd9\u662f\u5229\u7528\u4e86\u5e8f\u5217\u89e3\u5305\u7684\u7279\u6027<\/li>\n
      • Python \u80fd\u5728\u4e00\u6761\u8bed\u53e5\u4e2d\u5b9e\u73b0\u53d8\u91cf\u4ea4\u6362\uff0c\u4e0d\u9700\u5f15\u5165\u4e2d\u95f4\u53d8\u91cf\uff0c\u5728\u53d8\u91cf\u6570\u5c11\u4e8e 4 \u4e2a\u65f6\uff08 3.8 \u7248\u672c\u8d77\u662f\u5c11\u4e8e 5 \u4e2a\uff09\uff0cCPython \u662f\u5229\u7528\u4e86 ROT_* \u6307\u4ee4\u6765\u4ea4\u6362\u6808\u4e2d\u7684\u5143\u7d20\uff0c\u5f53\u53d8\u91cf\u6570\u8d85\u51fa\u65f6\uff0c\u5219\u662f\u5229\u7528\u4e86\u5e8f\u5217\u89e3\u5305\u7684\u7279\u6027\u3002<\/li>\n
      • \u5e8f\u5217\u89e3\u5305\u662f Python \u7684\u4e00\u5927\u7279\u6027\uff0c\u4f46\u662f\u5728\u672c\u6587\u7684\u4f8b\u5b50\u4e2d\uff0cCPython \u89e3\u91ca\u5668\u5728\u5c0f\u5c0f\u7684\u64cd\u4f5c\u4e2d\u8fd8\u63d0\u4f9b\u4e86\u51e0\u4e2a\u4f18\u5316\u7684\u6307\u4ee4\uff0c\u8fd9\u7edd\u5bf9\u4f1a\u8d85\u51fa\u5927\u591a\u6570\u4eba\u7684\u8ba4\u77e5<\/li>\n<\/ul>\n
        \u5982\u679c\u4f60\u89c9\u5f97\u672c\u6587\u5206\u6790\u5f97\u4e0d\u9519\uff0c\u90a3\u4f60\u5e94\u8be5\u4f1a\u559c\u6b22\u8fd9\u4e9b\u6587\u7ae0\uff1a<\/p>\n
        1 \u3001Python \u4e3a\u4ec0\u4e48\u4f7f\u7528\u7f29\u8fdb\u6765\u5212\u5206\u4ee3\u7801\u5757\uff1f<\/p>\n
        2 \u3001Python \u7684\u7f29\u8fdb\u662f\u4e0d\u662f\u53cd\u4eba\u7c7b\u7684\u8bbe\u8ba1\uff1f<\/p>\n
        3 \u3001Python \u4e3a\u4ec0\u4e48\u4e0d\u7528\u5206\u53f7\u4f5c\u8bed\u53e5\u7ec8\u6b62\u7b26\uff1f<\/p>\n
        4 \u3001Python \u4e3a\u4ec0\u4e48\u6ca1\u6709 main \u51fd\u6570\uff1f\u4e3a\u4ec0\u4e48\u6211\u4e0d\u63a8\u8350\u5199 main \u51fd\u6570\uff1f<\/p>\n
        5 \u3001Python \u4e3a\u4ec0\u4e48\u63a8\u8350\u86c7\u5f62\u547d\u540d\u6cd5\uff1f<\/p>\n
        6 \u3001Python \u4e3a\u4ec0\u4e48\u4e0d\u652f\u6301 i++ \u81ea\u589e\u8bed\u6cd5\uff0c\u4e0d\u63d0\u4f9b ++ \u64cd\u4f5c\u7b26\uff1f<\/p>\n
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