CODEWITHSUNDEEP
pythonpython-2.7lxmlelementtree
bzzWomp
bzzWomp

Reputation: 136

Sorting XML tags by child elements Python

I have a number of 'root' tags with children 'name'. I want to sort the 'root' blocks, ordered alphabetically by the 'name' element. Have tried lxml / etree / minidom but can't get it working... I can't get it to parse the value inside the tags, and then sort the parent root tags.

<?xml version='1.0' encoding='UTF-8'?>
  <roots>
    <root>
      <path>//1.1.1.100/Alex</path>
      <name>Alex Space</name>
    </root>
    <root>
      <path>//1.1.1.101/Steve</path>
      <name>Steve Space</name>
    </root>
    <root>
      <path>//1.1.1.150/Bethany</path>
      <name>Bethanys</name>
    </root>
</roots>

Here is what I have tried:

import xml.etree.ElementTree as ET

    def sortchildrenby(parent, child):
        parent[:] = sorted(parent, key=lambda child: child)


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

sortchildrenby(root, 'name')
for child in root:
    sortchildrenby(child, 'name')


tree.write('output.xml')

Upvotes: 1

Views: 3438

Answers (2)

Padraic Cunningham
Padraic Cunningham

Reputation: 180391

If you want to put the name nodes first:

x = """
  <roots>
    <root>
      <path>//1.1.1.100/Alex</path>
      <name>Alex Space</name>
    </root>
    <root>
      <path>//1.1.1.101/Steve</path>
          <name>Bethanys</name>
    </root>
    <root>
      <path>//1.1.1.150/Bethany</path>
        <name>Steve Space</name>
    </root>
</roots>"""

import lxml.etree as et
tree = et.fromstring(x)

for r in tree.iter("root"):
    r[:] = sorted(r, key=lambda ch: -(ch.tag == "name"))

print(et.tostring(tree).decode("utf-8"))

Which would give you:

<roots>
    <root>
      <name>Alex Space</name>
    <path>//1.1.1.100/Alex</path>
      </root>
    <root>
      <name>Bethanys</name>
    <path>//1.1.1.101/Steve</path>
          </root>
    <root>
      <name>Steve Space</name>
    <path>//1.1.1.150/Bethany</path>
        </root>
</roots>

But there is no need to sort if you just want to add them first, you can just remove and reinsert the name into index 0:

import lxml.etree as et
tree = et.fromstring(x)

for r in tree.iter("root"):
    ch = r.find("name")
    r.remove(ch)
    r.insert(0, ch)

print(et.tostring(tree).decode("utf-8"))

If the nodes are actually not in sorted order and you want to rearrange the roots node alphabetically:

x = """
  <roots>
    <root>
      <path>//1.1.1.100/Alex</path>
      <name>Alex Space</name>
    </root>
    <root>
      <path>//1.1.1.101/Steve</path>
         <name>Steve Space</name>
    </root>
    <root>
       <path>//1.1.1.150/Bethany</path>
       <name>Bethanys</name>
    </root>
</roots>"""
import lxml.etree as et
tree = et.fromstring(x)

tree[:] = sorted(tree, key=lambda ch: ch.xpath("name/text()"))

print(et.tostring(tree).decode("utf-8"))

Which would give you:

 <roots>
    <root>
      <path>//1.1.1.100/Alex</path>
      <name>Alex Space</name>
    </root>
    <root>
       <path>//1.1.1.150/Bethany</path>
       <name>Bethanys</name>
    </root>
    <root>
      <path>//1.1.1.101/Steve</path>
         <name>Steve Space</name>
    </root>
</roots>

You can also combine with either of the first two approach two also rearrange the root nodes putting name first.

Upvotes: 5

Chaitanya Sama
Chaitanya Sama

Reputation: 330

Try this:

import xml.etree.ElementTree as ET


xml="<?xml version='1.0' encoding='UTF-8'?><roots><root><path>//1.1.1.100/Alex</path><name>Alex Space</name></root><root><path>//1.1.1.101/Steve</path><name>Steve Space</name></root><root><path>//1.1.1.150/Bethany</path><name>Bethanys</name></root></roots>"
oldxml = ET.fromstring(xml)

names = []
for rootobj in oldxml.findall('root'):
    names.append(rootobj.find('name').text)

newxml = ET.Element('roots')
for name in sorted(names):
    for rootobj in oldxml.findall('root'):
        if name == rootobj.find('name').text:
            newxml.append(rootobj)
ET.dump(oldxml)
ET.dump(newxml)

I'm reading from a variable and dumpin it on screen.

You can change it read from file and dump it to a file like you need.

Upvotes: -1

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