Python: xml.etree.ElementTree - prefix 'sac' not found in prefix map

Question

First of all, I'm an R Programmer. My team needs to translate my RScript to Python, in order to extract some data from XML and convert that to JSON.

According to the documentation, and particulary this answer:

How do I parse XML in Python?

I've done the following:

OPTION 1

import xml.etree.ElementTree
e = xml.etree.ElementTree.parse('boleta1A.xml').getroot()


for atype in e.findall('cbc:ID'):
    print(atype.text)

Getting any results.

OPTION 2

import xml.etree.ElementTree as ET
tree = ET.parse('boleta1A.xml')
root = tree.getroot()

root.findall("./sac:AdditionalMonetaryTotal/cbc:ID").text


Here, I'm getting: 

Traceback (most recent call last):

  File "C:\ProgramData\Anaconda3\lib\site-packages\IPython\core\interactiveshell.py", line 2862, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)

  File "<ipython-input-29-2eefd6f96456>", line 5, in <module>
    root.findall("./sac:AdditionalMonetaryTotal/cbc:ID").text

  File "C:\ProgramData\Anaconda3\lib\xml\etree\ElementPath.py", line 304, in findall
    return list(iterfind(elem, path, namespaces))

  File "C:\ProgramData\Anaconda3\lib\xml\etree\ElementPath.py", line 283, in iterfind
    token = next()

  File "C:\ProgramData\Anaconda3\lib\xml\etree\ElementPath.py", line 83, in xpath_tokenizer
    raise SyntaxError("prefix %r not found in prefix map" % prefix)

  File "<string>", line unknown
SyntaxError: prefix 'sac' not found in prefix map

Here I think I need to add the namespace, but I'm not understanding well why and what for from the documentation:

https://docs.python.org/2.7/library/xml.etree.elementtree.html#parsing-xml-with-namespaces

XML FILE:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:ccts="urn:un:unece:uncefact:documentation:2" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ext="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2" xmlns:qdt="urn:oasis:names:specification:ubl:schema:xsd:QualifiedDatatypes-2" xmlns:sac="urn:sunat:names:specification:ubl:peru:schema:xsd:SunatAggregateComponents-1" xmlns:schemaLocation="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2 ..\xsd\maindoc\UBLPE-Invoice-2.0.xsd" xmlns:udt="urn:un:unece:uncefact:data:specification:UnqualifiedDataTypesSchemaModule:2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <ext:UBLExtensions>
        <ext:UBLExtension>
            <ext:ExtensionContent>
                <sac:AdditionalInformation>
                    <sac:AdditionalMonetaryTotal>
                        <cbc:ID>1001</cbc:ID>
                        <cbc:PayableAmount currencyID="PEN">388.3</cbc:PayableAmount>
                    </sac:AdditionalMonetaryTotal>
                    <sac:AdditionalProperty>
                        <cbc:ID>1000</cbc:ID>
                        <cbc:Value><![CDATA[CUATROCIENTOS SESENTA Y UN CON 56 /100 NUEVOS SOLES]]></cbc:Value>
                    </sac:AdditionalProperty>
                </sac:AdditionalInformation>
            </ext:ExtensionContent>
        </ext:UBLExtension>
    </ext:UBLExtensions>
</Invoice>

PLUS: I'm using a Jupyter Notebook, would you recommend this? Or are there, in the python world, something more similar to RStudio?

Thank you!

Python: xml.etree.ElementTree - prefix 'sac' not found in prefix map

0 Answers0