python返回xmlblock并删除编码标签

Question

我正在尝试编辑一个 xml 文件。

我得到的文件（存储新信息的位置）如下所示：

    <Symbols>
        <Symbol>
            <Name TaskPrio="1">dummyName</Name>
            <Type>dummyType</Type>
            <Comment>
                <!dummyComment>
            </Comment>
            <IGroup>Number</IGroup>
            <IOffset>Number</IOffset>
            <BitSize>Number</BitSize>
        </Symbol>
        <Symbol>
            <Name TaskPrio="1">dummyName</Name>
            <Type>dummyType</Type>
            <Comment>
                <!dummyComment>
            </Comment>
            <IGroup>Number</IGroup>
            <IOffset>Number</IOffset>
            <BitSize>Number</BitSize>
        </Symbol>
        ...
   </Symbols>

我需要插入新信息的文件部分（不同的 xml 文件）如下所示：

<VariableList>
  <Variable>
    <Name Type="4" AreaType="1" Address="0" Bit="0" Description="DummyDescription" Group="DummyGroup" Shared="0" Retentive="0" DynamicSettings="DummyDinamycSettings">VariableName</Name>
    <EnableTrace>0</EnableTrace>
    <EnableOPCUAServer>0</EnableOPCUAServer>
    <EnableOPCServer>0</EnableOPCServer>
    <EnableNetworkClient>0</EnableNetworkClient>
    <EnableMapRealTimeToDB>0</EnableMapRealTimeToDB>
  </Variable>
</VariableList>

我已经设法找出我需要的信息并将其格式化为我想要的 xmlblock：

<?xml version="1.0" ?>
<Variable>
  <Name Type="4" AreaType="1" Address="0" Bit="0" Description="DummyDescription" Group="DummyGroup" Shared="0" Retentive="0" DynamicSettings="DummyDinamycSettings">VariableName</Name>
  <EnableTrace>0</EnableTrace>
  <EnableOPCUAServer>0</EnableOPCUAServer>
  <EnableOPCServer>0</EnableOPCServer>
  <EnableNetworkClient>0</EnableNetworkClient>
  <EnableMapRealTimeToDB>0</EnableMapRealTimeToDB>
</Variable>

<?xml version="1.0" ?>
<Variable>
  <Name Type="4" AreaType="1" Address="0" Bit="0" Description="DummyDescription" Group="DummyGroup" Shared="0" Retentive="0" DynamicSettings="DummyDinamycSettings">VariableName</Name>
  <EnableTrace>0</EnableTrace>
  <EnableOPCUAServer>0</EnableOPCUAServer>
  <EnableOPCServer>0</EnableOPCServer>
  <EnableNetworkClient>0</EnableNetworkClient>
  <EnableMapRealTimeToDB>0</EnableMapRealTimeToDB>
</Variable>

使用以下代码：

    def getVarBlock(self, variables, stationName):
        def prettify(elem):
            """Return a pretty-printed XML string for the Element.
            """
            rough_string = ET.tostring(elem, 'utf-8')
            reparsed = minidom.parseString(rough_string)
            return reparsed.toprettyxml(indent="  ")

        end_list = []
        for vars in variables:
            varTyp = '0'
            xmlVariable = ET.Element('Variable')
            name = ET.SubElement(xmlVariable, 'Name')
            if vars['Name'].startswith(self.settings.type0Vars[0]):                             
                varTyp = '0'
                name.attrib['Type'] = '0'
            elif vars['Name'].startswith(self.settings.type2Vars[0]):                           
                varTyp = '2'
                name.attrib['Type'] = '2'
            elif vars['Name'].startswith(self.settings.type4Vars[0]):                           
                varTyp = '4'
                name.attrib['Type'] = '4'
            elif vars['Name'].startswith(self.settings.type6Vars[0]):                           
                varTyp = '6'
                name.attrib['Type'] = '6'
            elif vars['Name'].startswith(self.settings.type7Vars[0]):                           
                varTyp = '7'
                name.attrib['Type'] = '7'
            elif self.settings.type10Vars[0] in vars['Name']:                                     
                varTyp = '10'
                name.attrib['Type'] = '10'
            elif vars['Name'].startswith(self.settings.type11Vars[0]):                          
                varTyp = '11'
                name.attrib['Type'] = '11'
            else:
                name.attrib['Type'] = ' '

            name.attrib['AreaType'] = '1'
            name.attrib['Address'] = '0'
            name.attrib['Bit'] = '0'
            name.attrib['Description'] = vars['Comment']

            if vars['Name'].startswith('r'):
                name.attrib['Group'] = 'ANALOG'
            elif vars['Name'].startswith('b'):
                name.attrib['Group'] = 'DIGITAL'
            elif vars['Name'].startswith('st'):
                name.attrib['Group'] = 'STRUCTURES'
            else:
                name.attrib['Group'] = 'VARIABLES'

            name.attrib['Shared'] = '0'
            name.attrib['Retentive'] = '0'
            name.attrib['DynamicSettings'] = '[DRV]TwinCAT.Sta=' + stationName + '|SA=.' + vars['Name'] + '|Typ='+ varTyp +''
            name.text = vars['Name']

            enableTrace = SubElement(xmlVariable, 'EnableTrace')
            enableTrace.text = '0'

            enableOPCUAServer = SubElement(xmlVariable, 'EnableOPCUAServer')
            enableOPCUAServer.text = '0'

            enableOPCServer = SubElement(xmlVariable, 'EnableOPCServer')
            enableOPCServer.text = '0'

            enableNetworkClient = SubElement(xmlVariable, 'EnableNetworkClient')
            enableNetworkClient.text = '0'

            enableMapRealTimeToDB = SubElement(xmlVariable, 'EnableMapRealTimeToDB')
            enableMapRealTimeToDB.text = '0'

            end_list.append(prettify(xmlVariable))

        for line in end_list:
            print(line)

        return print(xmlVariable)

这是我遇到的问题：

• 为什么块由新行和编码标签分隔？
• 我如何摆脱编码标签？
• 以及如何以一种体面的方式返回函数中的新 xmlblocks 以便稍后在写入文件时使用？

Answer 1

仅使用 lxml 漂亮地打印元素

>>> from lxml import etree
>>> e1 = etree.Element("root")
>>> e2 = etree.Element("child")
>>> e2.text = "algo"
>>> e1.append(e2)
>>> etree.tostring(e1,pretty_print=True)
b'<root>\n  <child>algo</child>\n</root>\n'

>>> etree.tostring(e1,pretty_print=True).decode('utf-8')
'<root>\n  <child>algo</child>\n</root>\n'

>>> print(etree.tostring(e1,pretty_print=True))
<root>
  <child>algo</child>
</root>

顶部没有 XML 声明，只有元素的内容。

这将创建字符串的 XML 表示，打印时将包含 XML 声明

minidom.parseString(rough_string)

Answer 2

@LMC

我设法实现了你的建议，它给了我我需要的输出。 但是当我全部打印出来时，我只得到带有字符 '\\n' 而不是“漂亮”的字符。

我像这样修改了函数，我希望我能正确解释你的答案。

        def prettify(elem):
            pretty = ET.tostring(elem,pretty_print=True)
            return pretty