使用Python中的ElementTree解析具有名称空间的XML [英] Parsing XML with namespaces using ElementTree in Python
问题描述
我有一个xml,它的一小部分看起来像这样:
I have an xml, small part of it looks like this:
<?xml version="1.0" ?>
<i:insert xmlns:i="urn:com:xml:insert" xmlns="urn:com:xml:data">
<data>
<image imageId="1"></image>
<content>Content</content>
</data>
</i:insert>
当我使用 ElementTree
解析并保存时它将其保存到我看到的文件中:
When i parse it using ElementTree
and save it to a file i see following:
<ns0:insert xmlns:ns0="urn:com:xml:insert" xmlns:ns1="urn:com:xml:data">
<ns1:data>
<ns1:image imageId="1"></ns1:image>
<ns1:content>Content</ns1:content>
</ns1:data>
</ns0:insert>
为什么更改前缀并将其放置在各处?使用 minidom
我没有这种问题。是否已配置? ElementTree
的文档非常少。
问题是,这样的解析后我找不到任何节点,例如 image
-如果我使用它,无论有没有命名空间都找不到它例如 {namespace}图片
或仅图片
。为什么?
Why does it change prefixes and put them everywhere? Using minidom
i don't have such problem. Is it configured? Documentation for ElementTree
is very poor.
The problem is, that i can't find any node after such parsing, for example image
- can't find it with or without namespace if i use it like {namespace}image
or just image
. Why's that? Any suggestions are strongly appreciated.
我已经尝试过的内容:
import xml.etree.ElementTree as ET
tree = ET.parse('test.xml')
root = tree.getroot()
for a in root.findall('ns1:image'):
print a.attrib
这将返回错误,而另一个则不返回任何内容:
This returns an error and the other one returns nothing:
for a in root.findall('{urn:com:xml:data}image'):
print a.attrib
我也试图像这样使用命名空间并使用它:
I also tried to make namespace like this and use it:
namespaces = {'ns1': 'urn:com:xml:data'}
for a in root.findall('ns1:image', namespaces):
print a.attrib
它不返回任何内容。我在做什么错了?
It returns nothing. What am i doing wrong?
推荐答案
此片段来自您的问题,
for a in root.findall('{urn:com:xml:data}image'):
print a.attrib
不输出任何内容,因为它只查找直接的 {urn:com:xml:data}图像
树根的子代。
does not output anything because it only looks for direct {urn:com:xml:data}image
children of the root of the tree.
此代码稍作修改,
for a in root.findall('.//{urn:com:xml:data}image'):
print a.attrib
将打印 {'imageId':'1'}
,因为它使用的是。/ /
,它会在所有级别上选择匹配的子元素。
will print {'imageId': '1'}
because it uses .//
, which selects matching subelements on all levels.
参考: https://docs.python.org/2/library/xml.etree.elementtree.html#supported-xpath-syntax 。
令人讨厌的是,ElementTree不仅保留了默认情况下是原始名称空间前缀,但请记住,无论如何前缀都不重要。 register_namespace()
函数可用于在对XML进行序列化时设置所需的前缀。该功能对解析或搜索没有任何影响。
It is a bit annoying that ElementTree does not just retain the original namespace prefixes by default, but keep in mind that it is not the prefixes that matter anyway. The register_namespace()
function can be used to set the wanted prefix when serializing the XML. The function does not have any effect on parsing or searching.
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