{"id":562,"date":"2018-03-31T10:09:00","date_gmt":"2018-03-31T02:09:00","guid":{"rendered":"http:\/\/zkeeer.space\/?p=562"},"modified":"2018-03-31T10:10:02","modified_gmt":"2018-03-31T02:10:02","slug":"%e3%80%8a%e6%b5%81%e7%95%85%e7%9a%84python%e3%80%8b%e8%af%bb%e4%b9%a6%e7%ac%94%e8%ae%b0-%e7%ac%ac8%e7%ab%a0","status":"publish","type":"post","link":"http:\/\/zkeeer.space\/?p=562","title":{"rendered":"\u300a\u6d41\u7545\u7684Python\u300b\u8bfb\u4e66\u7b14\u8bb0–\u7b2c8\u7ae0"},"content":{"rendered":"
1.\u8bfe\u4e0a\u8001\u5e08\u7ecf\u5e38\u8bb2\u7684\u53d8\u91cf\u770b\u4e3a\u76d2\u5b50\uff0c\u5176\u5b9e\u53d8\u91cf\u5e94\u8be5\u770b\u505a\u6807\u8bc6\u3002<\/strong><\/div>\n
<\/div>\n
<\/div>\n
2.python\u4e2d\uff0cis\u6bd4\u8f83\u7684\u662f\u6807\u8bc6\u5373\u5185\u5b58\u5730\u5740\uff1b==\u6bd4\u8f83\u7684\u662f\u503c<\/strong>\u3002\u8fd9\u5c31\u6d89\u53ca\u5230\u4e86\u6548\u7387\u95ee\u9898\uff0cis\u7ecf\u5e38\u7528\u6765\u6bd4\u8f83\u53d8\u91cf\u548c\u5355\u4f8b\u503c\uff0c\u5373\u6700\u5e38\u4f7f\u7528\u7684\u662f\u7528is\u68c0\u67e5\u53d8\u91cf\u7ed1\u5b9a\u7684\u503c\u662f\u4e0d\u662fNone\uff0ca is None \/ a is not None\u3002is\u7684\u8fd0\u7b97\u901f\u5ea6\u6bd4==\u5feb<\/strong>\uff0c\u56e0\u4e3ais\u4e0d\u80fd\u91cd\u8f7d\uff1b==\u662fpython\u4e2d\u7684\u8bed\u6cd5\u7cd6\uff0c\u7b49\u540c\u4e8e__eq__()\uff0c\u7ee7\u627f\u81eaobject\u7684__eq__\u3002\u5728\u76f8\u7b49\u6027\u6d4b\u8bd5\u4e2d\u53ef\u80fd\u4f1a\u6d89\u53ca\u5230\u5927\u91cf\u7684\u5de5\u4f5c\uff0c\u4f8b\u5982\u6bd4\u8f83\u5927\u578b\u96c6\u5408\u548c\u5d4c\u5957\u5c42\u7ea7\u8f83\u6df1\u7684\u7ed3\u6784\u3002<\/div>\n
<\/div>\n
<\/div>\n
3.\u5143\u7ec4\u4e0epython\u96c6\u5408\uff08\u5217\u8868\uff0c\u5b57\u5178\uff0c\u96c6…\uff09\u4e00\u6837\uff0c\u4fdd\u5b58\u7684\u662f\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u800cstr\u3001bytes\u3001array.array\u7b49\u5355\u4e00\u5e8f\u5217\u662f\u6241\u5e73\u7684\uff0c\u800c\u662f\u5728\u8fde\u7eed\u7684\u5185\u5b58\u4e2d\u4fdd\u5b58\u7684\u6570\u636e\u672c\u8eab\u3002<\/div>\n
<\/div>\n
<\/div>\n
4.\u5143\u7ec4\u7684\u76f8\u5bf9\u4e0d\u53ef\u53d8\u6027<\/strong>\u3002\u5143\u7ec4\u7684\u7269\u7406\u5185\u5bb9\uff08\u5373\u4fdd\u5b58\u7684\u5f15\u7528\uff09\u4e0d\u53ef\u53d8\uff0c\u4e5f\u5c31\u662f\u8bf4\u5143\u7ec4\u7684\u6807\u8bc6\u4e0d\u53ef\u53d8\u3002\u4f46\u662f\u5143\u7ec4\u4e2d\u7684\u53ef\u53d8\u5bf9\u8c61\u4ecd\u4e0d\u53d7\u9650\u5236\uff0c\u4e3e\u4f8b\u6765\u8bf4\u5143\u7ec4\u4e2d\u7684\u5217\u8868\u53ef\u53d8\uff0c\u5c31\u6b64\u6765\u8bf4\u8fd9\u4e2a\u5143\u7ec4\u4e2d\u7684\u503c\u662f\u53ef\u53d8\u7684\u3002<\/div>\n
<\/div>\n
<\/div>\n
5.\u63a8\u8350www.pythontutor.com\u7f51\u7ad9\uff0c\u53ef\u89c6\u5316\u4ee3\u7801\u6267\u884c\u8fc7\u7a0b\u3002<\/strong><\/div>\n
<\/div>\n
<\/div>\n
6.\u4f7f\u7528\u6d45\u590d\u5236\u65f6\uff0c\u64cd\u4f5c\u5bb9\u6613\u4f46\u662f\u5f97\u5230\u7684\u7ed3\u679c\u53ef\u80fd\u4e0d\u662f\u4f60\u60f3\u8981\u7684\u3002\u4f7f\u7528\u6d45\u590d\u5236\uff0c\u526f\u672c\u662f\u5f15\u7528\u5bf9\u8c61\u7684\u6807\u8bc6\uff0c\u5bf9\u672c\u4f53\u7684\u53ef\u53d8\u5bf9\u8c61\u505a\u4e86\u64cd\u4f5c\u65f6\uff0c\u4f1a\u5f71\u54cd\u5230\u526f\u672c\uff1b\u4f46\u662f\u5bf9\u526f\u672c\uff08\u5bf9\u8c61\uff09\u4e0d\u53ef\u53d8\u5bf9\u8c61\u64cd\u4f5c\u65f6\uff0c\u4f1a\u6539\u53d8\u6240\u5f15\u7528\u7684\u5bf9\u8c61\uff0c\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u5143\u7ec4\u7ed9\u526f\u672c\uff08\u5bf9\u8c61\uff09\uff0c\u8fd9\u65f6\u526f\u672c\u7684\uff08\u5bf9\u8c61\uff09\u7684id\u53d8\u4e86\uff0c\u800c\u5bf9\u8c61\uff08\u526f\u672c\uff09\u7684id\u4e0d\u53d8\u3002<\/div>\n
\u5bf9\u4e8e\u4e0d\u53ef\u53d8\u5143\u7ec4\u4fee\u6539\u7684\u4f8b\u5b50\uff1a<\/div>\n
\n
t1 = (1, 2)\r\nt2 = t1\r\nprint(id(t1), t1)\r\nprint(id(t2), t2)\r\n\r\nt1 += (3, 4)   # \u6b64\u5904\u53ef\u4ee5\u6539\u6210t2 += (3, 4)\r\nprint(id(t1), t1)\r\nprint(id(t2), t2)<\/pre>\n<\/div>\n
<\/code><\/div>\n
\n
<\/div>\n
7.\u6df1\u590d\u5236\u7684\u610f\u601d\u662f\uff0c\u526f\u672c\u4e0d\u5171\u4eab\u5185\u90e8\u5bf9\u8c61\u7684\u5f15\u7528\u3002copy\u6a21\u5757\u63d0\u4f9b\u4e86deepcopy()\u548ccopy()\u51fd\u6570\u3002copy()\u51fd\u6570\u6267\u884c\u7684\u662f\u6d45\u590d\u5236\uff0c\u5bf9\u8c61\u548c\u526f\u672c\u7684\u6539\u53d8\u4f1a\u76f8\u4e92\u5f71\u54cd\uff1bdeepcopy()\u51fd\u6570\u6267\u884c\u7684\u662f\u6df1\u590d\u5236\uff0c\u5bf9\u8c61\u548c\u526f\u672c\u4e92\u4e0d\u5f71\u54cd\u3002<\/div>\n
copy\u548cdeepcopy\u7684\u4f8b\u5b50\uff08\u6d41\u7545\u7684python\uff09\uff1a<\/div>\n
<\/p>\n<\/div>\n
<\/div>\n
\n
import copy\r\n\r\n\r\nclass Bus:\r\n    def __init__(self, passengers=None):\r\n        if passengers == None:\r\n            self.passengers = []\r\n        else:\r\n            self.passengers = passengers\r\n\r\n    def pick(self, name):\r\n        self.passengers.append(name)\r\n\r\n    def drop(self, name):\r\n        self.passengers.remove(name)\r\n\r\n\r\nbus1 = Bus(['zhang', 'lee', 'wang'])\r\nbus2 = copy.copy(bus1)\r\nbus3 = copy.deepcopy(bus1)\r\n\r\nprint()\r\nprint(id(bus1), id(bus1.passengers), bus1.passengers)\r\nprint(id(bus2), id(bus2.passengers), bus2.passengers)\r\nprint(id(bus3), id(bus3.passengers), bus3.passengers)\r\n\r\nbus2.drop('zhang')\r\nprint()\r\nprint(id(bus1), id(bus1.passengers), bus1.passengers)\r\nprint(id(bus2), id(bus2.passengers), bus2.passengers)\r\nprint(id(bus3), id(bus3.passengers), bus3.passengers)\r\n\r\n\r\nbus1.pick('liu')\r\nprint()\r\nprint(id(bus1), id(bus1.passengers), bus1.passengers)\r\nprint(id(bus2), id(bus2.passengers), bus2.passengers)\r\nprint(id(bus3), id(bus3.passengers), bus3.passengers)<\/pre>\n<\/div>\n
<\/div>\n
\n
<\/div>\n
<\/div>\n
8.\u4f46\u662f\u6df1\u590d\u5236\u6d89\u53ca\u5230\u5faa\u73af\u5f15\u7528<\/strong>\u7684\u60c5\u51b5\u3002deepcopy\u5904\u7406\u5faa\u73af\u5f15\u7528\u7684\u65f6\u5019\uff0c\u4f1a\u8bb0\u4f4f\u590d\u5236\u8fc7\u7684\u5bf9\u8c61\uff0c\u56e0\u6b64\u5904\u7406\u8d77\u6765\u4e0d\u4f1a\u9677\u5165\u5faa\u73af\u4e2d\u3002<\/div>\n
deepcopy\u7684\u4f8b\u5b50\uff1a<\/div>\n<\/div>\n
<\/div>\n
\n
import copy\r\n\r\na = [10, 20]\r\nb = [a, 30]\r\na.append(b)\r\nprint(a)\r\n\r\nc = copy.deepcopy(a)\r\nprint(c)<\/pre>\n<\/div>\n
<\/div>\n
\n
<\/div>\n
<\/div>\n
9.python\u552f\u4e00\u652f\u6301\u7684\u4f20\u53c2\u65b9\u5f0f\uff1a\u5171\u4eab\u4f20\u53c2\uff08call by sharing\uff09\u3002\u5171\u4eab\u4f20\u53c2\u6307\u7684\u662f\u51fd\u6570\u5f62\u53c2\u83b7\u5f97\u7684\u662f\u5b9e\u53c2\u4e2d\u5404\u4e2a\u5f15\u7528\u7684\u526f\u672c\uff0c\u5373\u5b9e\u53c2\u7684\u522b\u540d\u3002\u53ef\u5f15\u8d77\u7684\u95ee\u9898\u662f\uff0c\u80fd\u591f\u4fee\u6539\u4f20\u5165\u7684\u53ef\u53d8\u53c2\u6570\u3002<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
10.\u6ca1\u6709\u6307\u5b9a\u53c2\u6570\u7684\u5b9e\u4f8b\uff08\u7f3a\u7701\u53c2\u6570\u7684\u5b9e\u4f8b\uff09\u4f1a\u5171\u4eab\u4e00\u4e2a\u53ef\u53d8\u5bf9\u8c61\uff08\u5f53\u53ef\u53d8\u5bf9\u8c61\u662f\u5f62\u53c2\u65f6\uff09\u3002\u5f53\u4e0d\u786e\u5b9a\u662f\u4e0d\u662f\u9700\u8981\u4fee\u6539\u5f62\u53c2\u65f6\uff0c\u5efa\u8bae\u521b\u5efa\u526f\u672c\u3002\u5982\u4f55\u521b\u5efa\u526f\u672c\uff0c\u770b\u4ee5\u4e0b\u5b9e\u4f8b\uff1a<\/div>\n
<\/div>\n
<\/p>\n
class Bus:\r\n    def __init__(self, passengers=None):\r\n        if passengers==None:\r\n            self.passengers=[]\r\n        else:\r\n            self.passengers=passengers<\/pre>\n<\/div>\n
\n
\u4ee5\u4e0a\u5224\u65ad\u4e86\u662f\u5426\u5f62\u53c2\u4e3a\u7f3a\u7701\uff0c\u82e5\u662f\u5219\u521b\u5efa\u526f\u672c\uff0c<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
11.del\u548c\u5783\u573e\u56de\u6536\u3002del\u51fd\u6570\u4e0d\u5220\u9664\u5bf9\u8c61\uff0c\u53ea\u5220\u9664\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u5f53\u5bf9\u8c61\u7684\u5f15\u7528\u4e3a0\u662f\uff0c\u5bf9\u8c61\u4f1a\u88ab\u5f53\u4f5c\u5783\u573e\u56de\u6536\uff08\u6b64\u65f6\u5bf9\u8c61\u4e0d\u53ef\u83b7\u53d6\uff09\u3002\uff08https:\/\/emptysqua.re\/blog\/pypy-garbage-collection-and-a-deadlock\/ \u5bf9__del__\u65b9\u6cd5\u7684\u6070\u5f53\u7528\u6cd5\u548c\u4e0d\u5f53\u7528\u6cd5\u505a\u4e86\u8ba8\u8bba\uff09<\/div>\n
<\/div>\n
<\/div>\n
<\/div>\n
12.\u5f31\u5f15\u7528\u3002\u5f31\u5f15\u7528\u4e0d\u4f1a\u589e\u52a0\u5f15\u7528\u6570\u91cf\uff0c\u4e0d\u5f71\u54cd\u5783\u573e\u56de\u6536\u3002\u5f31\u5f15\u7528\u7684\u5e94\u7528\uff0c\u5f53\u51fa\u73b0 \u5faa\u73af\u5f15\u7528\u6216\u8005\u4e00\u7ec4\u5bf9\u8c61\u76f8\u4e92\u5f15\u7528\uff0c\u800c\u6ca1\u6709\u88ab\u5176\u4ed6\u5bf9\u8c61\u76f4\u63a5\u5f15\u7528\u5e76\u4e14\u4e0d\u53ef\u8bbf\u95ee\uff0c\u5219\u8fd9\u4e9b\u5bf9\u8c61\u5c31\u80fd\u6c38\u4e45\u7684\u6d3b\u4e0b\u6765\uff0c\u65e0\u6cd5\u88ab\u56de\u6536\u3002\u5f53\u6709\u7a0b\u5e8f\u6301\u7eed\u4e0d\u65ad\u5730\u4ea7\u751f\u8fd9\u6837\u7684\u5bf9\u8c61\u65f6\uff0c\u5c31\u4f1a\u53d1\u751f\u5185\u5b58\u6cc4\u6f0f\u3002\u5f31\u5f15\u7528 \u7528\u6765\u89e3\u51b3\u4ee5\u4e0a\u95ee\u9898\u3002<\/div>\n
weakref\u7c7b\u662f\u4f4e\u5c42\u63a5\u53e3\uff0c\u4f9b\u9ad8\u7ea7\u7528\u9014\u4f7f\u7528\uff0c\u5e94\u5c3d\u91cf\u4f7f\u7528WeakKeyDictionary\u3001WeakValueDictionary\u3001WeakSet\u3001finalize\uff0c\u4e0d\u5efa\u8bae\u81ea\u5df1\u52a8\u624b\u521b\u5efa\u548c\u5904\u7406weakref.ref\u5b9e\u4f8b\u3002<\/div>\n
<\/div>\n
\u5b9e\u4f8b\uff1a<\/div>\n
<\/div>\n
<\/p>\n<\/div>\n
\n
import sys\r\nimport weakref\r\n\r\nclass Student:\r\n    def __init__(self, name=None):\r\n        if name==None:\r\n            self.name=\"None\"\r\n        else:\r\n            self.name=name\r\n\r\nS = Student('zhang')\r\nprint(sys.getrefcount(S))\r\n\r\nwr = weakref.ref(S)\r\nprint(sys.getrefcount(S))\r\n\r\nprint(S)\r\nprint(wr)\r\n\r\nS1=wr()\r\nprint(sys.getrefcount(S))\r\n\r\nS1=None\r\nprint(sys.getrefcount(S))\r\nS=None\r\nprint(sys.getrefcount(S))\r\n\r\nprint(wr)<\/pre>\n<\/div>\n
\n
<\/div>\n
<\/div>\n
<\/div>\n
13.\u5f31\u5f15\u7528\u7684\u5c40\u9650\u3002\u4e0d\u662f\u6bcf\u4e2apython\u5bf9\u8c61\u90fd\u53ef\u4ee5\u4f5c\u4e3a\u5f31\u5f15\u7528\u7684\u76ee\u6807\u3002\u4f8b\u5982list\u548cdict\u7684\u5b9e\u4f8b\u4e0d\u80fd\u4f5c\u4e3a\u6240\u6307\u5bf9\u8c61\u3002\u4f46\u662f\u5176\u5b50\u7c7b\u53ef\u4ee5\uff0c\u4f8b\u5982\uff1a<\/div>\n
<\/div>\n
<\/p>\n
class MyList(list):\r\n    def __init__():\r\n        pass<\/pre>\n
 <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
1.\u8bfe\u4e0a\u8001\u5e08\u7ecf\u5e38\u8bb2\u7684\u53d8\u91cf\u770b\u4e3a\u76d2\u5b50\uff0c\u5176\u5b9e\u53d8 … More \u300a\u6d41\u7545\u7684Python\u300b\u8bfb\u4e66\u7b14\u8bb0–\u7b2c8\u7ae0<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,15],"tags":[11,52],"_links":{"self":[{"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/posts\/562"}],"collection":[{"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/zkeeer.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=562"}],"version-history":[{"count":3,"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/posts\/562\/revisions"}],"predecessor-version":[{"id":573,"href":"http:\/\/zkeeer.space\/index.php?rest_route=\/wp\/v2\/posts\/562\/revisions\/573"}],"wp:attachment":[{"href":"http:\/\/zkeeer.space\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=562"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/zkeeer.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=562"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/zkeeer.space\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=562"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}