{"id":151,"date":"2019-04-29T21:58:31","date_gmt":"2019-04-29T13:58:31","guid":{"rendered":"http:\/\/i.pegasi.top\/?p=151"},"modified":"2019-04-29T22:10:35","modified_gmt":"2019-04-29T14:10:35","slug":"python%e4%b8%ad%e5%85%b3%e4%ba%8elist-copy%e7%9a%84%e9%99%b7%e9%98%b1","status":"publish","type":"post","link":"https:\/\/www.4-xx.com\/index.php\/2019\/04\/29\/python%e4%b8%ad%e5%85%b3%e4%ba%8elist-copy%e7%9a%84%e9%99%b7%e9%98%b1\/","title":{"rendered":"python\u4e2d\u5173\u4e8elist.copy()\u7684\u9677\u9631"},"content":{"rendered":"

\u4eca\u5929\u9065\u611f\u8bfe\u6b63\u597d\u5b66\u5230\u5377\u79ef\u8fd0\u7b97\uff0c\u7136\u540e\u53c8\u5e03\u7f6e\u4e86\u4f5c\u4e1a\u3002\u53ef\u662f\u624b\u5de5\u4e00\u4e2a\u4e2a\u7b97\uff08\u6572\u8ba1\u7b97\u5668\uff09\u592a\u7d2f\u4e86\uff0c\u4e8e\u662f\u6211\u5c31\u5728\u4e0b\u4e00\u8282\u8ba1\u7b97\u673a\u8bfe\u4e0a\u4e89\u53d6\u5077\u61d2\u2192_\u2192\u6bd4\u8f83\u987a\u5229\u7684\u662f\uff0c\u61d2\u662f\u5077\u6210\u4e86\u3002\u4f46\u662f\u5199\u7684\u7a0b\u5e8f\u6709\u4e2a\u5c0fbug\u2014\u2014\u5c31\u662f\u4f1a\u6539\u53d8\u539f\u59cb\u7684\u8f93\uff01\u5165\uff01\u6570\uff01\u636e\uff01<\/p>\n

\u4f5c\u4e3a\u4e00\u4e2a\u5f3a\u8feb\u75c7\uff0c\u8f93\u5165\u6570\u636e\u80af\u5b9a\u8981\u6709\u5907\u4efd\u7684\u561b\uff01\u4e8e\u662f\u4fbf\u5f00\u59cb\u67e5\u627e\u539f\u56e0\uff1a\u4e00\u5f00\u59cb\u8ba4\u4e3a\u662f\u7c7b\u7684\u95ee\u9898\uff0c\u540e\u6765\u53d1\u73b0\u95ee\u9898\u5e76\u4e0d\u8fd9\u4e48\u7b80\u5355\u2014\u2014<\/p>\n

\"\"<\/p>\n

\u5982\u56fe\uff0cself.table\u662f\u539f\u59cb\u8f93\u5165\u6570\u636e\uff0cres\u662f\u6682\u5b58\u7684\u7ed3\u679c\u3002\u5148\u662f\u628aself.table\u590d\u5236\u4e00\u4efd\u7ed9res.table\uff0c\u7136\u540e\u5bf9res.table\u8fdb\u884c\u5904\u7406\u3002\u55ef\uff0c\u4e00\u5207\u90fd\u5f88\u6b63\u5e38\uff01\u7136\u540e\u4e00\u8fd0\u884c\u2026\u2026\u5367\u69fd\uff1fself.table\u600e\u4e48\u4e5f\u5168\u53d8\u62104\u4e86\uff1f\u8fd9\u4e0d\u5bf9\u554a\uff01\u6211\u4e0d\u662fcopy\u4e86\u561b\uff01\u5bf9\u4e86\uff0c\u4e00\u5b9a\u662f\u6211copy\u7528\u5f97\u4e0d\u5bf9\uff0c\u4e8e\u662f\u6211\u5728idle\u4e0b\u8fdb\u884c\u4e86\u5982\u4e0b\u6d4b\u8bd5\uff1a<\/p>\n

>>> lst=[1,2]<\/p>\n

>>> a=lst.copy()<\/p>\n

>>> a[0]=999<\/p>\n

>>> a<\/p>\n

[999, 2]<\/p>\n

>>> lst<\/p>\n

[1, 2]<\/p><\/blockquote>\n

\u5f88\u6b63\u5e38\u554a\uff01\u8fd9\u4e0d\u662f\u5bf9\u7684\u561b\uff1f\u540e\u6765\u901a\u8fc7\u548c\u540c\u5b66\u7684\u8ba8\u8bba\uff0c\u53d1\u73b0\u4e86\u8fd9\u4e48\u4e00\u4e2a\u795e\u5947\u7684\u73b0\u8c61\uff1a<\/p>\n

>> >lst=[1,2]<\/p>\n

>>> a=lst.copy()<\/p>\n

>>> a[0]=999<\/p>\n

>>> a<\/p>\n

[999, 2]<\/p>\n

>>> lst<\/p>\n

[1, 2]<\/p>\n

>>> lst=[1,2]<\/p>\n

>>> a=lst.copy()<\/p>\n

>>> lst is a<\/p>\n

False<\/p>\n

>>> lst[0] is a[0]<\/p>\n

True<\/p>\n

>>> a[0]=999<\/p>\n

>>> lst[0] is a[0]<\/p>\n

False<\/p><\/blockquote>\n

\u54c7\uff01\u539f\u6765copy\u540e\u7684\u5217\u8868\u786e\u5b9e\u548c\u539f\u5217\u8868\u4e0d\u662f\u4e00\u4e2a\u4e1c\u897f\uff0c\u4f46\u662f\u5217\u8868\u4e2d\u5bf9\u5e94\u7684\u5143\u7d20\u8fd8\u662f\u4e00\u4e2a\u4e1c\u897f\u3002\u4f46\u662f\u7531\u4e8e\u6574\u6570\u4e0d\u53ef\u88ab\u66f4\u6539\uff0c\u6240\u4ee5\u5f53a[0]=999\u65f6\uff0cpython\u4f1a\u65b0\u5f00\u8f9f\u4e00\u4e2a\u5185\u5b58\u5b58999\u8fd9\u4e2a\u503c\uff0c\u6240\u4ee5\u5185\u5b58\u5730\u5740\u53c8\u4e0d\u4e00\u6837\u4e86\u3002<\/p>\n

\u56de\u5230\u6700\u5f00\u59cb\u7684\u7a0b\u5e8f\u4e2d\uff0c\u7531\u4e8e\u88abcopy\u7684\u5217\u8868\u65f6\u4e00\u4e2a\u5d4c\u5957\u5217\u8868\uff0c\u5373\u5217\u8868\u91cc\u7684\u5143\u7d20\u8fd8\u662f\u5217\u8868\u3002\u800c\u5217\u8868\u662f\u53ef\u4fee\u6539\u7684\uff0c\u6240\u4ee5\u5bfc\u81f4\u5c3d\u7ba1\u770b\u4e0a\u53bb\u5217\u8868\u88abcopy\u4e86\u4e00\u4e2a\u526f\u672c\uff0c\u91cc\u9762\u7684\u5143\u7d20\u8fd8\u662f\u4fdd\u6301\u7740\u5173\u8054\u6027\u3002\u6240\u4ee5\uff0c\u6539\u4e86res.table[x][y]\u5c31\u76f8\u5f53\u4e8e\u6539\u4e86self.table[x][y]\u3002<\/p>\n

\u90a3\u4e48\u8fd9\u4e2a\u95ee\u9898\u600e\u4e48\u89e3\u51b3\u5462\uff1f\u5f88\u7b80\u5355\uff0c\u5176\u5b9e\u901a\u8fc7copy\u6a21\u5757\u7684copy.deepcopy\u65b9\u6cd5\u5c31\u884c\u4e86\u3002\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n

\"\"<\/p>\n

 <\/p>\n

\u6700\u540e\u7684\u6700\u540e\uff0c\u5176\u5b9e\u6211\u5f88\u4e45\u4ee5\u524d\uff08\u4e5f\u6ca1\u591a\u4e45\uff09\u5728\u54ea\u91cc\u770b\u5230\u8fc7copy\u548cdeepcopy\u51fd\u6570\u8fd9\u4e2a\u4e1c\u897f\uff0c\u4e5f\u66fe\u7ecf\u7406\u89e3\u8fc7\u8fd9\u4e9b\u5185\u5bb9\uff0c\u4f46\u662f\u56e0\u4e3a\u8bb0\u6027\u4e0d\u597d= =\u4eca\u5929\u53c8\u5fd8\u6389\u4e86\uff0c\u6240\u4ee5\u5728\u81ea\u5df1\u7684\u535a\u5ba2\u4e2d\u6c34\u4e00\u7bc7\u8fd9\u6837\u7684\u6587\u7ae0\uff0c\u63d0\u9192\u81ea\u5df1\uff0c\u4e5f\u80fd\u4e3a\u540e\u6765\u7591\u60d1\u8005\u89e3\u60d1\u5427~<\/p>\n","protected":false},"excerpt":{"rendered":"

\u4eca\u5929\u9065\u611f\u8bfe\u6b63\u597d\u5b66\u5230\u5377\u79ef\u8fd0\u7b97\uff0c\u7136\u540e\u53c8\u5e03\u7f6e\u4e86\u4f5c\u4e1a\u3002\u53ef\u662f\u624b\u5de5\u4e00\u4e2a\u4e2a\u7b97\uff08\u6572\u8ba1\u7b97\u5668\uff09\u592a\u7d2f\u4e86\uff0c\u4e8e\u662f\u6211\u5c31\u5728\u4e0b\u4e00\u8282\u8ba1\u7b97\u673a\u8bfe\u4e0a\u4e89 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22,11],"tags":[24],"views":5249,"_links":{"self":[{"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/posts\/151"}],"collection":[{"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/comments?post=151"}],"version-history":[{"count":4,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/posts\/151\/revisions"}],"predecessor-version":[{"id":154,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/posts\/151\/revisions\/154"}],"wp:attachment":[{"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/media?parent=151"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/categories?post=151"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.4-xx.com\/index.php\/wp-json\/wp\/v2\/tags?post=151"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}