July 2017
Intermediate to advanced
398 pages
11h 54m
Chinese
Content preview from Python数据处理
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44
｜
第
3
章
写完上述代码后，保存文件并运行。如你所见，在
Python
中打开
JSON
文件并将其转换成
由字典组成的列表是非常容易的。下一节将探索更多自定义文件的处理方法。
3.3
XML
数据
XML
格式的数据既便于机器读取，也便于人工读取。但是对于本章的数据集来说，预
览并理解
CSV
文件和
JSON
文件要比
XML
文件容易得多。幸运的是，数据本身是相同
的，我们也比较熟悉。下载预期寿命数据的
XML
版本（下载地址：
http://apps.who.int/gho/
athena/data/GHO/WHOSIS_000001,WHOSIS_000002.xml?filter=COUNTRY:*;YEAR:2015
），
并将
XML
文件与本章其他内容保存在同一文件夹下。
如果文件的扩展名是
.xml
，那么它是
XML
数据。如果文件扩展名是
.html
或
.xhtml
，有时也可以用
XML
解析器来解析。
在处理所有数据时，我们先在代码编辑器中打开文件来预览一下。如果你滚动查看一下文
件，会发现我们在
CSV
的例子中已经熟悉的数据。但数据看起来又不大一样，因为它用
的是
XML
格式，使用了一种叫作
标签
的东西。
XML
是一种标记语言，也就是说，它具有包含格式化数据的文档结构。
XML
文档本质上只是格式特殊的数据文件。
下面的数据片段是我们要处理的
XML
数据的一个样本。在这个例子中，
<Observation />
、
<Dim />
和
<Display />
都是标签。标签（或节点）以层次化和结构化的方式保存数据：
<
GHO
...>
<
Data ...
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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.