如何使用 Beautiful Soup 修改 xml？

Question

我正在尝试修改 xml 文件中的查找数据元素。 xml的一个片段如下：

    <?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Options>
        <SampleRate>1000</SampleRate>
        <MaxStateSize>1</MaxStateSize>
        <MaxOutputSize>1</MaxOutputSize>
    </Options>

    <CustomDefinitions>
        <MyRser class="OhmicResistance">
            <Object class="LookupObj2dWithState">
                <RowState cacheref="Soc"/>
                <ColState cacheref="ThermalState"/>
                <LookupData>
                    0.02597518381655694900, 0.02513715386193249600, 0.02394715132636577100, 0.02325996676357371800, 0.02317075771456176400, 0.02277814077034603900, 0.02267913709322775700, 0.02258569292134297900, 0.02235026503875497600, 0.02222478423822949300, 0.02207606555239715500, 0.02198493491067361700, 0.02188144525929673300, 0.02167985791309091600, 0.02145797158835977700, 0.02137484908165417400, 0.02126561803424023600, 0.02124462299304301700, 0.02123310358079429400, 0.02126287857906075300, 0.02094998489960795500, 0.02073326148328196600, 0.02062489977511897100, 0.02038933084432985300;
                </LookupData>
                <MeasurementPointsRow desc="StateOfCharge">
                -5, 0, 7.100000e+00, 1.120000e+01, 16, 2.080000e+01, 2.560000e+01, 3.040000e+01, 3.520000e+01, 4.010000e+01, 4.490000e+01, 4.970000e+01, 5.450000e+01, 5.930000e+01, 6.420000e+01, 69, 7.380000e+01, 7.860000e+01, 8.350000e+01, 8.830000e+01, 9.310000e+01, 9.770000e+01, 100, 105
                </MeasurementPointsRow>
                <MeasurementPointsColumn desc="ThermalState">
                25
                </MeasurementPointsColumn>
            </Object>
        </MyRser>

我想修改查找数据并保存包含该修改的 xml 的副本。我是这样做的：

with open('....xml') as fp:
        contents = fp.read()
        soup = BeautifulSoup(contents, 'lxml')

        tag = soup.find(elem_name).find(elem_path).lookupdata
        tag.replace_with(str(values))

    #saves the modified data as a new xml version
    teslaname= elem_name+key
    
    with open('modified.xml', 'w') as file:  
        file.write(str(soup))
        file.close()

但是，当我这样做时，特定的修改已经完成，但它改变了 xml 结构。

 <?xml version="1.0" encoding="UTF-8"?><html><body><configuration>
<options>
<samplerate>1000</samplerate>
<maxstatesize>1</maxstatesize>
<maxoutputsize>1</maxoutputsize>
</options>
<customdefinitions>
<myrser class="OhmicResistance">
<object class="LookupObj2dWithState">
<rowstate cacheref="Soc"></rowstate>
<colstate cacheref="ThermalState"></colstate>
0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339, 0.02217779408499339
<measurementpointsrow desc="StateOfCharge">
                -5, 0, 7.100000e+00, 1.120000e+01, 16, 2.080000e+01, 2.560000e+01, 3.040000e+01, 3.520000e+01, 4.010000e+01, 4.490000e+01, 4.970000e+01, 5.450000e+01, 5.930000e+01, 6.420000e+01, 69, 7.380000e+01, 7.860000e+01, 8.350000e+01, 8.830000e+01, 9.310000e+01, 9.770000e+01, 100, 105
                </measurementpointsrow>
<measurementpointscolumn desc="ThermalState">
                25
                </measurementpointscolumn>
</object>
</myrser>

而且我想保留结构，只修改数据。我知道这可以通过 ElementTree 来完成，但是我需要我的代码如何运行，beautifulsoup 使用起来更简单。那么如果只考虑使用beautifulsoup，如何在不丢失xml的原始结构的情况下编辑并保存xml的副本？任何帮助将不胜感激。

Answer 1

要保持XML结构，写入文件时使用.prettify()方法：

file.write(str(soup.prettify()))

注：

BeautifulSoup 将 XML 标签转换为小写。
由于您使用上下文管理器打开文件，因此无需使用 file.close() 关闭文件，退出缩进块时文件将自动关闭。

Answer 2

使用 lxml，您可以执行以下操作：

from lxml import etree
config = """[your xml above, corrected - it's not well formed]"""
new_values = "1,2,3,4"
doc = etree.XML(config.encode())
target = doc.xpath('//LookupData')[0]
target.text = new_values
print(etree.tostring(doc).decode())

输出：

<Configuration>
    <Options>
        <SampleRate>1000</SampleRate>
        <MaxStateSize>1</MaxStateSize>
        <MaxOutputSize>1</MaxOutputSize>
    </Options>

    <CustomDefinitions>
        <MyRser class="OhmicResistance">
            <Object class="LookupObj2dWithState">
                <RowState cacheref="Soc"/>
                <ColState cacheref="ThermalState"/>
                <LookupData>1,2,3,4</LookupData>
                <MeasurementPointsRow desc="StateOfCharge">
                -5, 0, 7.100000e+00, 1.120000e+01, 16, 2.080000e+01, 2.560000e+01, 3.040000e+01, 3.520000e+01, 4.010000e+01, 4.490000e+01, 4.970000e+01, 5.450000e+01, 5.930000e+01, 6.420000e+01, 69, 7.380000e+01, 7.860000e+01, 8.350000e+01, 8.830000e+01, 9.310000e+01, 9.770000e+01, 100, 105
                </MeasurementPointsRow>
                <MeasurementPointsColumn desc="ThermalState">
                25
                </MeasurementPointsColumn>
            </Object>
        </MyRser>
        </CustomDefinitions>
    </Configuration>

如何使用 Beautiful Soup 修改 xml？

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