如何使用python替换xml中的元素

Question

sorry for my poor English. but i need your help ;(

i have 2 xml files.

one is:

<root>
<data name="aaaa">
<value>"old value1"</value>
<comment>"this is an old value1 of aaaa"</comment>
</data>
<data name="bbbb"> 
<value>"old value2"</value>
<comment>"this is an old value2 of bbbb"</comment>
</data>
</root>

two is:

<root>
<data name="aaaa">
<value>"value1"</value>
<comment>"this is a value 1 of aaaa"</comment>
</data>
<data name="bbbb"> 
<value>"value2"</value>
<comment>"this is a value2 of bbbb"</comment>
</data>
<data name="cccc"> 
<value>"value3"</value>
<comment>"this is a value3 of cccc"</comment>
</data>
</root>

one.xml will be updated from two.xml.

so, the one.xml should be like this.

one.xml(after) :

<root>
<data name="aaaa">
<value>"value1"</value>
<comment>"this is a value1 of aaaa"</comment>
</data>
<data name="bbbb"> 
<value>"value2"</value>
<comment>"this is a value2 of bbbb"</comment>
</data>
</root>

data name="cccc" is not exist in one.xml. therefore ignored.

actually what i want to do is

1. download two.xml(whole list) from db
2. update my one.xml (it contains DATA-lists that only the app uses) by two.xml

Any can help me please !! Thanks!!

============================================================== xml.etree.ElementTree
your code works with the example. but i found a problem in real xml file.

the real one.xml contains :

<?xml version="1.0" encoding="utf-8"?>
<root>
    <resheader name="resmimetype">
        <value>text/microsoft-resx</value>
    </resheader>
    <resheader name="version">
        <value>2.0</value>
    </resheader>
    <resheader name="reader">
        <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
    </resheader>
    <resheader name="writer">
        <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
    </resheader>

    <data name="NotesLabel" xml:space="preserve">
        <value>Hinweise:</value>
        <comment>label for input field</comment>
    </data>
    <data name="NotesPlaceholder" xml:space="preserve">
        <value>z . Milch kaufen</value>
        <comment>example input for notes field</comment>
    </data>
    <data name="AddButton" xml:space="preserve">
        <value>Neues Element hinzufügen</value>
        <comment>this string appears on a button to add a new item to the list</comment>
    </data>
</root>

it seems, resheader causes trouble. do you have any idea to fix?

Answer 1

You can use xml.etree.ElementTree and while there are propably more elegant ways, this should work on files that fit in memory if name s are unique in two.xml

import xml.etree.ElementTree as ET
tree_one = ET.parse('one.xml')
root_one = tree_one.getroot()
tree_two = ET.parse('two.xml')
root_two = tree_two.getroot()

data_two=dict((e.get("name"), e) for e in root_two.findall("data"))

for eo in root_one.findall("data"):
    name=eo.get("name")
    tail=eo.tail
    eo.clear()
    eo.tail=tail
    en=data_two[name]
    for k,v in en.items():
        eo.set(k,v)
    eo.extend(en.findall("*"))
    eo.text=en.text

tree_one.write("one.xml")

If your files do not fit in memory you can still use xml.dom.pulldom as long as single data entries do fit.