Reading XML file and fetching its attributes value in Python

6
votes

I have this XML file:

<domain type='kmc' id='007'>
  <name>virtual bug</name>
  <uuid>66523dfdf555dfd</uuid>
  <os>
    <type arch='xintel' machine='ubuntu'>hvm</type>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
  </os>
  <memory unit='KiB'>524288</memory>
  <currentMemory unit='KiB'>270336</currentMemory>
  <vcpu placement='static'>10</vcpu>

Now, I want parse this and fetch its attribute value. For instance, I want to fetch the uuid field. So what should be the proper method to fetch it, in Python?

7
pythonxmlxml-parsingpython-2.7
What have you tried? Googling "python xml" yields quite a few really useful results that should point you in the right direction. - Blender
there are a lot of examples but not pointing in the direction i want to go. I wnat to fetch attributes value. the examples i am seeing are to convert to xml file or to convert form an xml file - S.Ali

7 Answers

27
votes

Here's an lxml snippet that extracts an attribute as well as element text (your question was a little ambiguous about which one you needed, so I'm including both):

from lxml import etree
doc = etree.parse(filename)

memoryElem = doc.find('memory')
print memoryElem.text        # element text
print memoryElem.get('unit') # attribute

You asked (in a comment on Ali Afshar's answer) whether minidom (2.x, 3.x) is a good alternative. Here's the equivalent code using minidom; judge for yourself which is nicer:

import xml.dom.minidom as minidom
doc = minidom.parse(filename)

memoryElem = doc.getElementsByTagName('memory')[0]
print ''.join( [node.data for node in memoryElem.childNodes] )
print memoryElem.getAttribute('unit')

lxml seems like the winner to me.

12
votes

XML 

<data>
    <items>
        <item name="item1">item1</item>
        <item name="item2">item2</item>
        <item name="item3">item3</item>
        <item name="item4">item4</item>
    </items>
</data>

Python : 

from xml.dom import minidom
xmldoc = minidom.parse('items.xml')
itemlist = xmldoc.getElementsByTagName('item') 
print "Len : ", len(itemlist)
print "Attribute Name : ", itemlist[0].attributes['name'].value
print "Text : ", itemlist[0].firstChild.nodeValue
for s in itemlist :
    print "Attribute Name : ", s.attributes['name'].value
    print "Text : ", s.firstChild.nodeValue
2
votes

etree, with lxml probably:

root = etree.XML(MY_XML)
uuid = root.find('uuid')
print uuid.text
0
votes

Other people can tell you how to do it with the Python standard library. I'd recommend my own mini-library that makes this a completely straight forward.

>>> obj = xml2obj.xml2obj("""<domain type='kmc' id='007'>
... <name>virtual bug</name>
... <uuid>66523dfdf555dfd</uuid>
... <os>
... <type arch='xintel' machine='ubuntu'>hvm</type>
... <boot dev='hd'/>
... <boot dev='cdrom'/>
... </os>
... <memory unit='KiB'>524288</memory>
... <currentMemory unit='KiB'>270336</currentMemory>
... <vcpu placement='static'>10</vcpu>
... </domain>""")
>>> obj.uuid
u'66523dfdf555dfd'

http://code.activestate.com/recipes/534109-xml-to-python-data-structure/

0
votes

I would use lxml and parse it out using xpath //UUID

0
votes

Above XML does not have closing tag, It will give

etree parse error: Premature end of data in tag

Correct XML is:

<domain type='kmc' id='007'>
  <name>virtual bug</name>
  <uuid>66523dfdf555dfd</uuid>
  <os>
    <type arch='xintel' machine='ubuntu'>hvm</type>
    <boot dev='hd'/>
    <boot dev='cdrom'/>
  </os>
  <memory unit='KiB'>524288</memory>
  <currentMemory unit='KiB'>270336</currentMemory>
  <vcpu placement='static'>10</vcpu>
</domain>
0
votes

You can try parsing it with using (recover=True). you can do something like this.

parser = etree.XMLParser(recover=True)
tree = etree.parse('your xml file', parser)

I used this recently and it worked for me, you can try and see but in case you need to do any more complecated xml data extractions, you can take a look at this code i wrote for some project handling complex xml data extractions.