{"id":46,"date":"2016-03-23T09:44:01","date_gmt":"2016-03-23T01:44:01","guid":{"rendered":"http:\/\/www.5x44.cn\/?p=46"},"modified":"2023-04-11T16:42:03","modified_gmt":"2023-04-11T08:42:03","slug":"%e7%ac%ac%e4%b8%89%e7%ab%a0-list-dictionary%e5%92%8cset%e7%9a%84%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3%e5%92%8c%e5%ae%83%e4%bb%ac%e4%b9%8b%e9%97%b4%e7%9a%84%e5%85%b3%e7%b3%bb","status":"publish","type":"post","link":"https:\/\/www.5x44.cn\/?p=46","title":{"rendered":"\u7b2c\u4e09\u7ae0 list, dictionary\u548cset\u7684comprehension"},"content":{"rendered":"\n<p>\uff081\uff09os\u6a21\u5757\u53ef\u4ee5\u5f97\u5230\u5927\u91cf\u7684\u7cfb\u7edf\u4fe1\u606f\uff0c\u8fd9\u4e2a\u6a21\u5757\u662fpython\u81ea\u5e26\u7684\uff0c\u53ef\u4ee5\u5728\u4efb\u4f55\u65f6\u5019\uff0c\u4efb\u4f55\u4f4d\u7f6e\u5bfc\u5165\u3002os.path\u6a21\u5757\u5305\u542b\u4e86\u7528\u4e8e\u64cd\u7eb5\u6587\u4ef6\u548c\u76ee\u5f55\u7684\u51fd\u6570\uff1a<br>1\uff09os.path.join()\u5c06\u591a\u4e2a\u90e8\u5206\u8def\u5f84\u6784\u5efa\u4e00\u4e2a\u65b0\u7684\u8def\u5f84\uff0c\u5b83\u7684\u53c2\u6570\u53ef\u4ee5\u6709\u4efb\u610f\u6570\u91cf\u7684\u53c2\u6570\u3002<br>&gt;&gt;&gt; print(os.path.join(&#8216;\/usr\/local&#8217;, &#8216;apache2&#8217;))<br>\/usr\/local\/apache2<br>2\uff09\u4e0d\u8981\u81ea\u5df1\u6dfb\u52a0\u591a\u4f59\u7684\u659c\u7ebf\u8fde\u63a5\u8def\u5f84\uff0c\u800c\u662f\u4f7f\u7528os.path.join()\u8ba9python\u81ea\u5df1\u53bb\u505a\u8fd9\u4e9b\u4e8b\u3002<br>3\uff09os.path.expanduser()\u51fd\u6570\u8fd4\u56de\u7528\u6237\u7684home\u76ee\u5f55\u3002<br>4\uff09os.path.split()\u53ef\u4ee5\u8fd4\u56de\u76ee\u5f55\u540d\u548c\u6587\u4ef6\u540d\uff1bos.path.splitxt()\u51fd\u6570\u8fd4\u56de\u6587\u4ef6\u540d\u548c\u6587\u4ef6\u6269\u5c55\u540d\u3002<\/p>\n\n\n\n<p>\uff082\uff09glob\u6a21\u5757\u662f\u6807\u51c6python\u5e93\uff0c\u53ef\u4ee5\u83b7\u5f97\u76ee\u5f55\u7684\u5185\u5bb9\uff1a<br>&gt;&gt;&gt;import glob<br>&gt;&gt;&gt;glob.glob(&#8216;examples\/*.xml&#8217;)#\u83b7\u5f97examples\u76ee\u5f55\u4e0b\u7684xml\u6587\u4ef6\u3002<\/p>\n\n\n\n<p>\uff083\uff09python\u53ef\u4ee5\u8fd4\u56de\u6587\u4ef6\u7684\u5143\u6570\u636e\u5e76\u4e14\u4e0d\u7528\u6253\u5f00\u6587\u5e74\uff0c\u53ea\u8981\u6709\u6587\u4ef6\u540d\u5c31\u53ef\u4ee5\uff1a<br>1\uff09metadata=os.stat(filename)#\u8fd4\u56defilename\u7684\u5143\u6570\u636e\uff0c\u5b58\u5728metadata\u5bf9\u8c61\u91cc\u3002<br>2\uff09metadata.st_mtime#\u6587\u4ef6\u4fee\u6539\u65f6\u95f4\uff0c\u4f46\u662f\u4ee51970\u5e741\u67081\u65e50\u70b90\u79d2\u5f00\u59cb\uff0c\u5230\u73b0\u5728\u7684\u79d2\u6570\u3002\u4f46\u662f\u53ef\u4ee5\u7528time\u6a21\u5757\u8f6c\u6362\u6210\u5176\u5b83\u683c\u5f0f\u3002time.localtime(metadata.st_mtime)\u3002<br>3\uff09\u5728\u4ea4\u4e92\u5f0f\u547d\u4ee4\u884c\u91cc\u76f4\u63a5\u8f93\u5165metadata\u4f1a\u8f93\u51fa\u6240\u6709\u76f8\u5173\u5c5e\u6027\u3002<\/p>\n\n\n\n<p>\uff084\uff09os.path.realpath(filename)#\u7528\u4e8e\u8fd4\u56defilename\u7684\u7edd\u5bf9\u8def\u5f84\u3002<\/p>\n\n\n\n<p>\uff085\uff09\u5217\u8868\u63a8\u5bfc\u5f0f\uff08List Comprehension\uff09\u63d0\u4f9b\u4e86\u4e00\u79cd\u7b80\u4fbf\u7684\u5efa\u7acb\u5217\u8868\u7684\u65b9\u6cd5\uff0c\u53ea\u9700\u8981\u5728\u65b9\u62ec\u53f7\u91cc\u4f7f\u7528for\u8bed\u53e5\uff0cif\u8bed\u53e5\u6839\u636e\u6761\u4ef6\u987b\u8981\u6dfb\u52a0\uff0cfor\u4e4b\u524d\u662f\u7528\u4e8e\u8fd4\u56de\u5217\u8868\u7684\u5143\u7d20\uff0cfor\u4e4b\u540e\u662f\u8fed\u4ee3\u548c\u7b5b\u9009\u6761\u4ef6\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-green-cyan-color\">&#91;expr for var in iterable if condition]<\/mark><\/strong><\/code><\/pre>\n\n\n\n<p>\u4f8b\u5982\uff1a<br>&gt;&gt;&gt;a_list = [1,9,8,4]<br>&gt;&gt;&gt;[elem * 2 for elem in a_list]<br>&gt;&gt;&gt;a_list=[other * 2 for other in a_list if other&gt;5]#\u628aa_list\u4e2d\u5927\u4e8e5\u7684\u5143\u7d20\u5bfc\u51fa\uff0c\u518d\u4e582\u540e\uff0c\u5efa\u7acb\u4e00\u4e2a\u65b0\u5217\u8868\u3002\u4e2d\u95f4\u751f\u6210\u7684\u5217\u8868\u5728\u5185\u5b58\u4e2d\u4fdd\u5b58\uff0c\u4e0d\u4f1a\u7834\u574f\u539f\u6709\u7684\u5217\u8868\u3002<\/p>\n\n\n\n<p>\uff086\uff09dictionary Comprehension\u548cList Comprehension\u4e00\u6837\uff0c\u53ea\u4e0d\u8fc7\u7528\u82b1\u62ec\u53f7\u4ee3\u66ff\u65b9\u62ec\u53f7\u3002\u53ef\u4ee5\u901a\u8fc7\u8fd9\u4e2a\u65b9\u6cd5\u6765\u4ea4\u6362\u5b57\u5178\u4e2d\u7684key\u548cvalue\uff08value\u4e5f\u662f\u4e0d\u53ef\u4fee\u6539\u7684\u503c\uff0c\u5982\u679cvalue\u662f\u53ef\u4fee\u6539\u7684\u503c\uff0c\u90a3\u4f1a\u51fa\u9519\uff09<\/p>\n\n\n\n<p>\uff087\uff09set comprehension\u548c\u4e0a\u9762\u4e24\u79cd\u4e00\u6837\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\uff081\uff09os\u6a21\u5757\u53ef\u4ee5\u5f97\u5230\u5927\u91cf\u7684\u7cfb\u7edf\u4fe1\u606f\uff0c\u8fd9\u4e2a\u6a21\u5757\u662fpython\u81ea\u5e26\u7684\uff0c\u53ef\u4ee5\u5728\u4efb\u4f55\u65f6\u5019\uff0c\u4efb\u4f55\u4f4d\u7f6e\u5bfc\u5165\u3002os.path\u6a21\u5757\u5305\u542b\u4e86\u7528\u4e8e\u64cd\u7eb5\u6587\u4ef6\u548c\u76ee\u5f55\u7684\u51fd\u6570\uff1a1\uff09os.p&#8230;<\/p>\n<p class=\"read-more\"><a class=\"btn btn-default\" href=\"https:\/\/www.5x44.cn\/?p=46\"> Read More<span class=\"screen-reader-text\">  Read More<\/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":[3],"tags":[],"class_list":["post-46","post","type-post","status-publish","format-standard","hentry","category-dive-into-python3"],"_links":{"self":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/46","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=46"}],"version-history":[{"count":10,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions"}],"predecessor-version":[{"id":7378,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions\/7378"}],"wp:attachment":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=46"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=46"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=46"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}