July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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224
｜
第
11
章
11.2.1
检视
：
标记结构
当你想要抓取一个站点的时候，首先分析站点结构和标记语言。像在第
3
章学到的那样，
XML
的结构由节点和内容以及键和值组成。
HTML
非常相似。如果打开浏览器的开发者
工具，浏览检视（
Inspection
）、元素（
Elements
）或
DOM
标签，你会看到一系列的节点
和它们的值。节点和其包含的数据同我们在
XML
示例中看到的有一些不同——它们是
HTML
标签（表
11-1
列出了一些基本的标签）。
HTML
标签用来告诉你内容信息。如果你
想找到页面上的所有图片，查找
img
标签。
表11-1：基本的HTML标签
标签 描述 示例
head
用来存储元数据和文档的其
他必需信息
<head> <title>Best Title Ever</title> </head>
body
用来存储页面大部分内容
<body> <p>super short page</p> </body>
meta
用来存储元数据，例如站点
简短的描述或关键词
<meta name="keywords"content="tags, html">
h1
,
h2
，
h3
… 用来存储头部信息；数字越
小，头部越大
<h1>Really big one!</h1>
p
用来存储文本段落
<p>Here's my first paragraph.</p>
ul
，
ol
用来存储无序表（
ul
：圆点）
和有序表（
ol
：数字）
<ul><li>first bullet</li></ul>
li
用来存储列表对象；应该始
终位于一个列表
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.