Parsing nested XML structure using minidom in Python

Question

I am Python XML beginner and I have an issue to get data from the given XML file:

<?xml version="1.0" encoding="UTF-8"?>
<martif xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="en">
   <cat>
      <desc type="No">1</desc>
      <desc type="Main">DES1.1</desc>
      <desc type="Sub">DES1.2</desc>
      <lang xml:lang="EN">
         <t>
            <term>T1.1</term>
            <Typ type="TermType">main</Typ>
         </t>
         <t>
            <term>T1.2</term>
            <Typ type="TermType">option</Typ>
         </t>
      </lang>
      <lang xml:lang="FR">
         <t>
            <term>T1.3</term>
            <Typ type="TermType">main</Typ>
         </t>
         <t>
            <term>T1.4</term>
            <Typ type="TermType">option</Typ>
         </t>
      </lang>
   </cat>
   <cat>
      <desc type="No">2</desc>
      <desc type="Main">DES2.1</desc>
      <desc type="Sub">DES2.2</desc>
      <lang xml:lang="EN">
         <t>
            <term>T2.1</term>
            <Typ type="TermType">main</Typ>
         </t>
         <t>
            <term>T2.2</term>
            <Typ type="TermType">option</Typ>
         </t>
      </lang>
      <lang xml:lang="FR">
         <t>
            <term>T2.3</term>
            <Typ type="TermType">main</Typ>
         </t>
         <t>
            <term>T2.4</term>
            <Typ type="TermType">option</Typ>
         </t>
      </lang>
   </cat>
</martif>

The desired result should be:

Type:  Main      Category: DES1.1
Type:  Sub       Category: DES1.2
lang:  EN
Term:  T2.1
TermType: main
Term:  T1.2
TermType: option
lang:  FR
Term:  T1.3
Term Note: main
Term:  T1.4
TermType: option

Type:  Main      Category: DES2.1
Type:  Sub       Category: DES2.2
lang:  EN
Term:  T2.1
TermType: main
Term:  T2.2
TermType: option
lang:  FR
Term:  T2.3
Term Note: main
Term:  T2.4
TermType: option

I tried but I still have some issue to get the desired result, the issue is how to extract the data based on the given xml data structure.

Here is my code:

from xml.dom import minidom

doc = minidom.parse("data.xml")
descs = doc.getElementsByTagName("desc")

for desSetElem in descs:
      type = desSetElem.getAttribute("type")
      if type!='No':
        print('Type: ',type,'     Category:',desSetElem.firstChild.nodeValue)
        lang_termSetElem = doc.getElementsByTagName('lang')
        for lang_term in lang_termSetElem:
             # for lang_tig in lang_tigSetElem:
               lang_type=lang_term.getAttribute(('xml:lang'))
               print('lang: ',lang_type)
               print('Term: ',lang_term.getElementsByTagName("term")[0].firstChild.nodeValue)
               print('Term Type:',lang_term.getElementsByTagName("Typ")[0].firstChild.nodeValue)

Here the result I got:

Type:  Main      Category: DES1.1
lang:  EN
Term:  T1.1
Term Type: main
lang:  FR
Term:  T1.3
Term Type: main
lang:  EN
Term:  T2.1
Term Type: main
lang:  FR
Term:  T2.3
Term Type: main
Type:  Sub      Category: DES1.2
lang:  EN
Term:  T1.1
Term Type: main
lang:  FR
Term:  T1.3
Term Type: main
lang:  EN
Term:  T2.1
Term Type: main
lang:  FR
Term:  T2.3
Term Type: main
Type:  Main      Category: DES2.1
lang:  EN
Term:  T1.1
Term Type: main
lang:  FR
Term:  T1.3
Term Type: main
lang:  EN
Term:  T2.1
Term Type: main
lang:  FR
Term:  T2.3
Term Type: main
Type:  Sub      Category: DES2.2
lang:  EN
Term:  T1.1
Term Type: main
lang:  FR
Term:  T1.3
Term Type: main
lang:  EN
Term:  T2.1
Term Type: main
lang:  FR
Term:  T2.3
Term Type: main

Answer 1

Consider walking down the three levels of XML with your looping: <cat> , <desc> / <lang> , and <t> . Specifically, since <lang> is a sibling of <desc> it should not be a nested loop. Also, <t> elements would need to be iterated.

Consider also using F-strings (Python 3.6+) and line breaking to conform to PEP-8 standards of 80 characters.

from xml.dom import minidom

doc = minidom.parse("MiniDOMPrintOutput.xml")
cats = doc.getElementsByTagName("cat")

for catElem in cats:
    descs = catElem.getElementsByTagName("desc")
    for desSetElem in descs:
        type = desSetElem.getAttribute("type")
        if type != 'No':
            print(f"Type: {type.ljust(9)}"
                  f"Category: {desSetElem.firstChild.nodeValue}")

    lang_termSetElem = catElem.getElementsByTagName("lang")
    for lang_term in lang_termSetElem:
        lang_type = lang_term.getAttribute(("xml:lang"))
        print(f"lang: {lang_type}")

        lang_tigSetElem = lang_term.getElementsByTagName("t")
        for lang_tig in lang_tigSetElem:
            term = (lang_tig.getElementsByTagName('term')[0]
                            .firstChild
                            .nodeValue)
            Typ = (lang_tig.getElementsByTagName('Typ')[0]
                           .firstChild
                           .nodeValue)

            print(f"Term: {term}")
            print(f"Term Type: {Typ}")

Output

Type: Main     Category: DES1.1
Type: Sub      Category: DES1.2
lang: EN
Term: T1.1
Term Type: main
Term: T1.2
Term Type: option
lang: FR
Term: T1.3
Term Type: main
Term: T1.4
Term Type: option
Type: Main     Category: DES2.1
Type: Sub      Category: DES2.2
lang: EN
Term: T2.1
Term Type: main
Term: T2.2
Term Type: option
lang: FR
Term: T2.3
Term Type: main
Term: T2.4
Term Type: option