{"id":384600,"date":"2021-03-11T10:34:10","date_gmt":"2021-03-11T02:34:10","guid":{"rendered":"http:\/\/4563.org\/?p=384600"},"modified":"2021-03-11T10:34:10","modified_gmt":"2021-03-11T02:34:10","slug":"python-%ef%bc%9a%e5%a6%82%e4%bd%95%e9%81%bf%e5%85%8d%e6%9f%90%e4%b8%aa%e5%87%bd%e6%95%b0%e5%86%85%e7%9a%84%e7%b1%bb%e5%8f%8d%e5%a4%8d%e8%bf%9b%e8%a1%8c%e5%ae%9e%e4%be%8b%e5%8c%96%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=384600","title":{"rendered":"Python \uff1a\u5982\u4f55\u907f\u514d\u67d0\u4e2a\u51fd\u6570\u5185\u7684\u7c7b\u53cd\u590d\u8fdb\u884c\u5b9e\u4f8b\u5316\uff1f"},"content":{"rendered":"
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Python \uff1a\u5982\u4f55\u907f\u514d\u67d0\u4e2a\u51fd\u6570\u5185\u7684\u7c7b\u53cd\u590d\u8fdb\u884c\u5b9e\u4f8b\u5316\uff1f <\/h1>\n

<\/p>\n

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\u8cc7\u6df1\u5927\u4f6c : capbone <\/span> <\/i> 4<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n

\u5047\u8bbe\u6709\u4e00\u4e2a\u5305\u542b\u7c7b C<\/code> \u5b9e\u4f8b\u7684\u51fd\u6570 foo<\/code>\uff1a<\/p>\n

def foo(x):     bar = C()     return bar(x) <\/code><\/pre>\n
foo<\/code> \u8fd9\u4e2a\u51fd\u6570\u4f1a\u88ab\u67d0\u4e2a\u4e1a\u52a1\u53cd\u590d\u8c03\u7528\uff08\u6bd4\u5982\u6bcf\u5206\u949f 10,000 \u6b21\uff09\uff0c\u6709\u4ec0\u4e48\u529e\u6cd5\u80fd\u591f\u8ba9\u7c7b C<\/code> \u7684\u5b9e\u4f8b\u5316\u8fc7\u7a0b\uff08bar = C()<\/code>\uff09\u53ea\u5728\u7b2c\u4e00\u6b21\u88ab\u8c03\u7528\u7684\u65f6\u5019\u6267\u884c\u4e00\u6b21\u5462\uff1f\u6362\u53e5\u8bdd\u8bf4\uff0c\u7b2c\u4e00\u6b21\u8c03\u7528\u751f\u6210 bar<\/code> \u5bf9\u8c61\u540e\uff0c\u5982\u4f55\u628a\u5b83\u7f13\u5b58\u4f4f\uff0c\u8ba9\u7b2c\u4e8c\u6b21\u53ca\u540e\u7eed\u8c03\u7528\u90fd\u76f4\u63a5\u8f7d\u5165\u8fd9\u4e2a\u7f13\u5b58\u5bf9\u8c61\u5462\uff1f<\/p>\n
\u6709\u51e0\u4e2a\u9650\u5236\uff1a<\/p>\n
1 \u3001C<\/code> \u662f\u5728\u67d0\u4e2a\u7b2c\u4e09\u65b9\u5e93\u4e2d\u5b9e\u73b0\u7684\uff0c\u56e0\u6b64\u6ca1\u6cd5\u4fee\u6539\u6e90\u7801\u8ba9 C<\/code> \u6210\u4e3a\u5355\u4f8b\uff1b<\/p>\n
2 \u3001\u51fd\u6570 foo<\/code> \u7684\u53c2\u6570\u683c\u5f0f\u4e0d\u5141\u8bb8\u4fee\u6539\uff1b<\/p>\n
3 \u3001foo<\/code> \u53ef\u80fd\u4f1a\u88ab a.py \u8c03\u7528\uff0c\u4e5f\u53ef\u80fd\u88ab b.py \u8c03\u7528\uff0c\u6211\u5e0c\u671b\u5728\u8fd9\u4e24\u4e2a py \u6587\u4ef6\u6267\u884c\u7684\u8fc7\u7a0b\u4e2d bar<\/code> \u5bf9\u8c61\u662f\u72ec\u7acb\u5b58\u5728\u7684\uff0c\u56e0\u6b64\u597d\u50cf\u4e0d\u9002\u5408\u628a foo<\/code> \u5b9a\u4e49\u4e3a global<\/code>\uff1f<\/p>\n
\u5982\u679c\u6682\u4e14\u4e0d\u8003\u8651\u9650\u5236 3\uff0c\u6709\u6ca1\u6709\u4ec0\u4e48\u6bd4\u8f83\u597d\u7684\u65b9\u6cd5\u5b9e\u73b0\uff1f<\/p>\n<\/p><\/div>\n
 \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (12<\/span>)        <\/div>\n
 <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
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  • \n
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     \u8cc7\u6df1\u5927\u4f6c : ericls <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 “`
    class C:
     def __init__(self):
     print(“here”)<\/p>\n
    c_cache = {}
    def make_c():
     import inspect
     frame = inspect.stack()
     key = ‘.’.join([frame[1].filename, frame[1].function])
     if key not in c_cache:
     c_cache[key] = C()
     return c_cache[key]<\/p>\n
    def foo():
     c = make_c()<\/p>\n
    def bar():
     c = make_c()<\/p>\n
    for i in range(100):
     foo()<\/p>\n
    for i in range(100):
     bar()
    “`                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : ericls <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 https:\/\/gist.github.com\/ericls\/3a2a17c7dbceb15462d0fcbe259d2246