August 2022
Intermediate to advanced
441 pages
11h 26m
Chinese
Content preview from Python文本分析
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网页抓取与数据提取
｜
85
3.12
案例：通过正则表达式提取数据
浏览器是剖析文章的重要工具之一。我们打开
URL
，然后点击“查看源
代码”。首先，我们感兴趣的是这篇文章的标题。仔细看一看
HTML
，
该标题同时出现在了
<title>
和
<h1>
中。
[...]
<title>Banned
in
Boston: Without vaping, medical marijuana patients
must adapt – Reuters</title>
[...]
<h1 class="ArticleHeader_headline">Banned
in
Boston: Without vaping,
medical marijuana patients must adapt</h1>
[...]
HTML
代码会随着时间发生变化
本节中呈现的程序都是根据撰写本书之际的
HTML
代码编写的。然而，
发布商可以随时更改其网站结构，甚至删除内容。还有一种方法是使用
Wayback Machine
（
https://archive.org
）中的数据，其中包含路透社网站
的镜像，而且布局和
HTML
结构的快照也保留了下来。
此外，你还可以参考本书的
GitHub
存档。如果布局发生变化，而且程
序无法正常运行，则可以参照其上提供的替代链接（和站点地图）。
标题的提取可以使用正则表达式来实现，无需使用任何其他库。首先，下载文章，
并将其保存到如下本地文件中：“
us-health-vaping-marijuana-idUSKBN1WG4KT
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.