add xml node to xml file with python

I wonder if it is better add an element by opening file, search 'good place' and add string which contains xml code. Or use some 开发者_运维技巧library... i have no idea. I know how can i get nodes and properties from xml through for example lxml but what's the simpliest and the best way to add?

You could use lxml.etree.Element to make the xml node(s), and use append or insert to attach them into xml document:

data='''\
<root>
<node1>
  <node2 a1="x1"> ... </node2>
  <node2 a1="x2"> ... </node2>
  <node2 a1="x1"> ... </node2>
</node1>
</root>
'''
doc = lxml.etree.XML(data)
e=doc.find('node1')
child = lxml.etree.Element("node3",attrib={'a1':'x3'})
child.text='...'
e.insert(1,child)
print(lxml.etree.tostring(doc))

yields:

<root>
    <node1>
      <node2 a1="x1"> ... </node2>
      <node3 a1="x3">...</node3><node2 a1="x2"> ... </node2>
      <node2 a1="x1"> ... </node2>
    </node1>
    </root>

The safest way to add nodes to an XML document is to load it into a DOM, add the nodes programmatically and write it out again. There are several Python XML libraries. I have used minidom, but I have no reason to recommend it specifically over the others.