在 python 中通过 elementtree 解析 xml 时如何保留命名空间-尊龙凯时

问题描述

假设我有以下想要使用 python 的 elementtree 修改的 xml:

assume that i've the following xml which i want to modify using python's elementtree:

  
  ...
 

我正在对 xml 文件进行一些修改，如下所示:

i'm doing some modification on the xml file like this:

import xml.etree.elementtree as et
tree = et.parse('filename.xml')
# xml modification here
# save the modifications
tree.write('filename.xml')

那么 xml 文件看起来像:

then the xml file looks like:

  
  ...

如您所见，namepsace prefix 更改为 ns0.我知道使用 et.register_namespace() 提到 这里.

as you can see, the namepsace prefix changed to ns0. i'm aware of using et.register_namespace() as mentioned here.

et.register_namespace() 的问题在于:

1. 你需要知道prefix和uri
2. 它不能与默认命名空间一起使用.

例如如果 xml 看起来像:

e.g. if the xml looks like:

    
    ...
    

它将被转换为:

    
    ...
    

如您所见，默认命名空间更改为ns0.

as you can see, the default namespace is changed to ns0.

有没有办法用elementtree解决这个问题?

is there any way to solve this problem with elementtree?

推荐答案

elementtree 将替换那些未使用 et.register_namespace 注册的命名空间前缀.要保留命名空间前缀，您需要先注册它，然后再将修改写入文件.以下方法完成这项工作并在全局范围内注册所有命名空间，

elementtree will replace those namespaces' prefixes that are not registered with et.register_namespace. to preserve a namespace prefix, you need to register it first before writing your modifications on a file. the following method does the job and registers all namespaces globally,

def register_all_namespaces(filename):
    namespaces = dict([node for _, node in et.iterparse(filename, events=['start-ns'])])
    for ns in namespaces:
        et.register_namespace(ns, namespaces[ns])

这个方法应该在et.parse方法之前调用，这样命名空间将保持不变，

this method should be called before et.parse method, so that the namespaces will remain as unchanged,

import xml.etree.elementtree as et
register_all_namespaces('filename.xml')
tree = et.parse('filename.xml')
# xml modification here
# save the modifications
tree.write('filename.xml')