CODEWITHSUNDEEP
pythonxml
Stephen Belanger
Stephen Belanger

Reputation: 6361

How can I convert XML into a Python object?

I need to load an XML file and convert the contents into an object-oriented Python structure. I want to take this:

<main>
    <object1 attr="name">content</object>
</main>

And turn it into something like this:

main
main.object1 = "content"
main.object1.attr = "name"

The XML data will have a more complicated structure than that and I can't hard code the element names. The attribute names need to be collected when parsing and used as the object properties.

How can I convert XML data into a Python object?

Upvotes: 47

Views: 60890

Answers (7)

Hugo
Hugo

Reputation: 2185

I would suggest xsData (https://xsdata.readthedocs.io/en/latest/)

# Parse XML
from pathlib import Path
from tests.fixtures.primer import PurchaseOrder
from xsdata.formats.dataclass.parsers import XmlParser

xml_string = Path("tests/fixtures/primer/sample.xml").read_text()
parser = XmlParser()
order = parser.from_string(xml_string, PurchaseOrder)
order.bill_to

Upvotes: 1

Ryan Ginstrom
Ryan Ginstrom

Reputation: 14121

David Mertz's gnosis.xml.objectify would seem to do this for you. Documentation's a bit hard to come by, but there are a few IBM articles on it, including this one (text only version).

from gnosis.xml import objectify

xml = "<root><nodes><node>node 1</node><node>node 2</node></nodes></root>"
root = objectify.make_instance(xml)

print root.nodes.node[0].PCDATA # node 1
print root.nodes.node[1].PCDATA # node 2

Creating xml from objects in this way is a different matter, though.

Upvotes: 4

Peter Hoffmann
Peter Hoffmann

Reputation: 58664

It's worth looking at lxml.objectify.

xml = """<main>
<object1 attr="name">content</object1>
<object1 attr="foo">contenbar</object1>
<test>me</test>
</main>"""

from lxml import objectify

main = objectify.fromstring(xml)
main.object1[0]             # content
main.object1[1]             # contenbar
main.object1[0].get("attr") # name
main.test                   # me

Or the other way around to build xml structures:

item = objectify.Element("item")
item.title = "Best of python"
item.price = 17.98
item.price.set("currency", "EUR")

order = objectify.Element("order")
order.append(item)
order.item.quantity = 3
order.price = sum(item.price * item.quantity for item in order.item)

import lxml.etree
print(lxml.etree.tostring(order, pretty_print=True))

Output:

<order>
  <item>
    <title>Best of python</title>
    <price currency="EUR">17.98</price>
    <quantity>3</quantity>
  </item>
  <price>53.94</price>
</order>

Upvotes: 65

Soviut
Soviut

Reputation: 91545

I've been recommending this more than once today, but try Beautiful Soup (easy_install BeautifulSoup).

from BeautifulSoup import BeautifulSoup

xml = """
<main>
    <object attr="name">content</object>
</main>
"""

soup = BeautifulSoup(xml)
# look in the main node for object's with attr=name, optionally look up attrs with regex
my_objects = soup.main.findAll("object", attrs={'attr':'name'})
for my_object in my_objects:
    # this will print a list of the contents of the tag
    print my_object.contents
    # if only text is inside the tag you can use this
    # print tag.string

Upvotes: 9

JV.
JV.

Reputation: 2698

#@Stephen: 
#"can't hardcode the element names, so I need to collect them 
#at parse and use them somehow as the object names."

#I don't think thats possible. Instead you can do this. 
#this will help you getting any object with a required name.

import BeautifulSoup


class Coll(object):
    """A class which can hold your Foo clas objects 
    and retrieve them easily when you want
    abstracting the storage and retrieval logic
    """
    def __init__(self):
        self.foos={}        

    def add(self, fooobj):
        self.foos[fooobj.name]=fooobj

    def get(self, name):
        return self.foos[name]

class Foo(object):
    """The required class
    """
    def __init__(self, name, attr1=None, attr2=None):
        self.name=name
        self.attr1=attr1
        self.attr2=attr2

s="""<main>
         <object name="somename">
             <attr name="attr1">value1</attr>
             <attr name="attr2">value2</attr>
         </object>
         <object name="someothername">
             <attr name="attr1">value3</attr>
             <attr name="attr2">value4</attr>
         </object>
     </main>
"""

#

soup=BeautifulSoup.BeautifulSoup(s)


bars=Coll()
for each in soup.findAll('object'):
    bar=Foo(each['name'])
    attrs=each.findAll('attr')
    for attr in attrs:
        setattr(bar, attr['name'], attr.renderContents())
    bars.add(bar)


#retrieve objects by name
print bars.get('somename').__dict__

print '\n\n', bars.get('someothername').__dict__

output

{'attr2': 'value2', 'name': u'somename', 'attr1': 'value1'}


{'attr2': 'value4', 'name': u'someothername', 'attr1': 'value3'}

Upvotes: 1

user26294
user26294

Reputation: 5652

There are three common XML parsers for python: xml.dom.minidom, elementree, and BeautifulSoup.

IMO, BeautifulSoup is by far the best.

http://www.crummy.com/software/BeautifulSoup/

Upvotes: 0

RoboDev
RoboDev

Reputation: 4156

How about this

http://evanjones.ca/software/simplexmlparse.html

Upvotes: 1

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