XML ElementTree - indexing tags

Question

I have a XML file:

<sentence id="en_BlueRibbonSushi_478218345:2">
   <text>It has great sushi and even better service.</text>
</sentence>
<sentence id="en_BlueRibbonSushi_478218345:3">
   <text>The entire staff was extremely accomodating and tended to my every need.</text>
</sentence>
<sentence id="en_BlueRibbonSushi_478218345:4">
   <text>I&apos;ve been to this restaurant over a dozen times with no complaints to date.</text>
</sentence>

Using XML ElementTree, I would like to insert a tag <Opinion> that has an attribute category=. Say I have a list of chars list = ['a', 'b', 'c'], is it possible to incrementally asign them to each text so I have:

<sentence id="en_BlueRibbonSushi_478218345:2">
   <text>It has great sushi and even better service.</text>
   <Opinion category='a' />
</sentence>
<sentence id="en_BlueRibbonSushi_478218345:3">
   <text>The entire staff was extremely accomodating and tended to my every need.</text>
   <Opinion category='b' />
</sentence>
<sentence id="en_BlueRibbonSushi_478218345:4">
   <text>I&apos;ve been to this restaurant over a dozen times with no complaints to date.</text>
   <Opinion category='c' />
</sentence>

I am aware I can use the sentence id attribute but this would require a lot of restructuring of my code. Basically, I'd like to be able to index each sentence entry to align with my list index.

Answer 1

You can use the SubElement factory function to add elements to the tree. Assuming your XML data is in a variable called data, this will add the elements to your document tree:

import xml.etree.ElementTree as ET
tree = ET.XML(data)
for elem, category in zip(tree.findall('sentence'), ['a', 'b', 'c']):
    Opinion  = ET.SubElement(elem, 'Opinion')
    Opinion.set('category', category)

ET.dump(tree)  # prints the tree; tree.write('output.xml') is another option