使用Python附加在XML元素上

Question

I have xml named user_data.xml that contains:

<?xml version="1.0"?>
<users>
<user name="Rocky" id="1" age="38"/>
<user name="Steve" id="2" age="50"/>
<user name="Melinda" id="3" age="38"/>
</users>

and i want to add new element inside users something like:

<?xml version="1.0"?>
<users>
<user name="Rocky" id="1" age="38"/>
<user name="Steve" id="2" age="50"/>
<user name="Melinda" id="3" age="38"/>
<user name="Yondu" id="4" age="55"/>
</users>

and I've tried to do it using this python code:

class add_user:
        root_new  = ET.Element("users") 
    root_new.append((ET.fromstring('<user name="Yondu" id="4" age="55"/>')))
    tree = ET.ElementTree(root_new)
    tree.write(sys.stdout)
    for c in root_new:
        print(root_new)

but it's not working .

Any idea on how can I do it?

Answer 1

1. Parse input XML file/content by etree.fromstring()
2. Now you get object of root element.
3. Then use etree.Element() method to create New User element.
4. As our root element is users ie append new element to root element by append method.

Demo :

>>> from lxml import etree

>>> input_data = """<?xml version="1.0"?>
... <users>
... <user name="Rocky" id="1" age="38"/>
... <user name="Steve" id="2" age="50"/>
... <user name="Melinda" id="3" age="38"/>
... </users>"""

>>> root = etree.fromstring(input_data)

>>> new_user = etree.Element("user", {"name":"Yondu", "id":"4", "age": "55"})

>>> root.tag
'users'

>>> root.append(new_user)

>>> print etree.tostring(root, method="xml", pretty_print=True)
<users>
<user name="Rocky" id="1" age="38"/>
<user name="Steve" id="2" age="50"/>
<user name="Melinda" id="3" age="38"/>
<user age="55" name="Yondu" id="4"/></users>

>>> 

Note: Do necessary Exception handle.

lxml Documentation Link