How to access UBL 2.1 xml tag using python

Question

I need to access the tags in UBL 2.1 and modify them depend on the on the user input on python.

So, I used the ElementTree library to access the tags and modify them.

Here is a sample of the xml code:

<ns0:Invoice xmlns:ns0="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:ns1="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:ns2="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2">
    <ns1:ProfileID>reporting:1.0</ns1:ProfileID>
    <ns1:ID>0</ns1:ID>
    <ns1:UUID>dbdf65eb-5d66-47e6-bb0c-a84bbf7baa30</ns1:UUID>
    <ns1:IssueDate>2022-11-05</ns1:IssueDate>

---

The issue :

I want to access the tags but it is doesn't modifed and enter the loop I tried both ways:

mytree = ET.parse('test.xml')
myroot = mytree.getroot()
for x in myroot.find({xmlns:ns1=urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2}IssueDate}"):
x.text = '1999'
mytree.write('test.xml')

mytree = ET.parse('test.xml')
myroot = mytree.getroot()
for x in myroot.iter('./Invoice/AllowanceCharge/ChargeIndicator'):
    x.text = str('true')
mytree.write('test.xml')
 

---

None of them worked and modify the tag.

So the questions is : How can I reach the specific tag and modify it?

Answer 1

If you correct the namespace and the brakets in your for loop it works for a valid XML like (root tag must be closed!):

Input:

<?xml version="1.0" encoding="utf-8"?>
<ns0:Invoice xmlns:ns0="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:ns1="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:ns2="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2">
  <ns1:ProfileID>reporting:1.0</ns1:ProfileID>
  <ns1:ID>0</ns1:ID>
  <ns1:UUID>dbdf65eb-5d66-47e6-bb0c-a84bbf7baa30</ns1:UUID>
  <ns1:IssueDate>2022-11-05</ns1:IssueDate>
</ns0:Invoice>

Your repaired code:

import xml.etree.ElementTree as ET

tree = ET.parse('test.xml')
root = tree.getroot()

for elem in root.findall("{urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2}IssueDate"):
    elem.text = '1999'

tree.write('test_changed.xml', encoding='utf-8', xml_declaration=True)    
ET.dump(root)

Output:

<ns0:Invoice xmlns:ns0="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:ns1="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2">
    <ns1:ProfileID>reporting:1.0</ns1:ProfileID>
    <ns1:ID>0</ns1:ID>
    <ns1:UUID>dbdf65eb-5d66-47e6-bb0c-a84bbf7baa30</ns1:UUID>
    <ns1:IssueDate>1999</ns1:IssueDate>
</ns0:Invoice>