Compare xml strings and list out difference in Python

Question

I've been looking around, and though there are several options, none of them really fit my current problem.

I get two XML strings, str1 and str2 that have "User" nodes with childnodes detailing things like name, age, address, etc. From there I need to create a third XML File3 that exclusively contains the fields that have changed between the two while keeping the "name" node to identify that the change was done with that user.

str1:
<users>
 <user>
  <name>Marco</name>
  <height>1,76</height>
  <address>C:/ Far-away 34</address>
  <mail>marco@marco</mail>
 </user>
</users>

str2:
<users>
 <user>
  <name>Marco</name>
  <height>1,80</height>
  <address>C:/ Far-away 34</address>
  <mail></mail>
 </user>
</users>

It should spit out an XML with:

str3:

<users>
 <user>
  <name>Marco</name>
  <height>1,80</height>
  <mail></mail>
 </user>
</users>

With one of my main complications being that I am not told which nodes will be present (or whether or not they have childnodes) other than "name". May I know, how can we do that Python without installing any pip package?.

Answer 1

You can use ElementTree for this. Parse both XML strings into ElementTree objects, use iter() to iterate over the user elements in both, and compare the text of each element:

import xml.etree.ElementTree as ET

tree1 = ET.fromstring(str1)
tree2 = ET.fromstring(str2)

result = ET.Element('users')

for user1, user2 in zip(tree1.iter('user'), tree2.iter('user')):
    changed = ET.Element('user')
    changed.append(user1.find('name'))
    for elem1, elem2 in zip(user1, user2):
        if elem1.text != elem2.text:
            changed.append(elem2)
    if len(changed) > 1:
        result.append(changed)