在Python中解析XML

Question

我想从一个xml文件中提取文本。假设我在一个file.xml文件里有一些内容：

<s id="1792387-2">Castro Verde is situated in the Baixo Alentejo Subregion within a territory known locally as the Campo Branco (English: White Plains).</s>

我该如何从上面的内容中提取以下文本：

Castro Verde is situated in the Baixo Alentejo Subregion within a territory known locally as the Campo Branco (English: White Plains).

然后在对这些文本进行一些修改后，我想把修改后的文本用相同的标签返回，如下所示。

<s id="1792387-2"> Changed Text </s>

有什么建议吗？谢谢！

Answer 1

使用Python中的dom包来解析XML文件是我最喜欢的方法，具体可以参考这个链接：http://docs.python.org/py3k/library/xml.dom.minidom.html。

import xml.dom.minidom
d = xml.dom.minidom.parseString("<s id=\"1792387-2\">Castro Verde is situated in the Baixo Alentejo Subregion within a territory known locally as the Campo Branco (English: White Plains).</s>")
oldText = d.childNodes[0].childNodes[0].data
d.childNodes[0].childNodes[0].data = "Changed text"
d.toxml()

不过，这个方法并不能帮助你解析文本，所以我不太确定你具体想要什么。

Answer 2

有几个标准库的方法可以用来解析XML文件……但一般来说，ElementTree 是最简单的选择：

from xml.etree import ElementTree
from StringIO import StringIO
doc = ElementTree.parse(StringIO("""<doc><s id="1792387-2">Castro…</s><s id="1792387-3">Other stuff</s></doc>"""))
for elem in doc.findall("s"):
    print "Text:", elem.text
    elem.text = "new text"
    print "New:", ElementTree.dump(elem)

如果你的XML文件是从文件中读取的，你可以使用：

f = open("path/to/foo.xml")
doc = ElementTree.parse(f)
f.close()
… use `doc` …

Answer 3

LXML 让这个过程变得特别简单。

>>> from lxml import etree
>>> text = '''<s id="1792387-2">Castro Verde is situated in the Baixo Alentejo Subregion within a territory known locally as the Campo Branco (English: White Plains).</s>'''
>>> def edit(s):
...     return 'Changed Text'
... 
>>> t = etree.fromstring(text)
>>> t.text = edit(t.text)
>>> etree.tostring(t)
'<s id="1792387-2">Changed Text</s>'