使用python（使用xmlns属性）进行XML解析不起作用

Question

It's my first time trying to parse XML with python so answer could be simple but I can't figure this out.

I'm using ElementTree to parse some XML file. Problem is that I cannot get any result inside the tree when having this attribute:

<package xmlns="http://apple.com/itunes/importer" version="software5.1">

When removing this attribute everything works great. To be clear I mean when changing first line of XML file to:

<package>

Everything works great.

What am I doing wrong?

Here is my code:

import xml.etree.ElementTree as ET

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

p = root.find(".//intervals/interval")

print p
for interval in root.iterfind(".//intervals/interval"):
    start_date = interval.find('start_date').text
    end_date = interval.find('end_date').text
    print start_date, end_date

Please help. Thanks!

UPDATE: The XML file:

<?xml version="1.0" encoding="UTF-8"?>
<package xmlns="http://apple.com/itunes/importer" version="software5.1">
<metadata_token>TOKEN</metadata_token>
<provider>Provider Name</provider>
<team_id>Team_ID_Here</team_id>
<software>
    <!--Apple ID: 01234567-->
    <vendor_id>vendorSKU</vendor_id>
    <read_only_info>
        <read_only_value key="apple-id">01234567</read_only_value>
    </read_only_info>
    <software_metadata>
        <versions>
            <version string="1.0">
                <locales>
                    <locale name="en-US">
                        <title>title text</title>
                        <description>Description text</description>
                        <keywords>
                            <keyword>key1</keyword>
                            <keyword>key2</keyword>
                        </keywords>
                        <version_whats_new>New things here</version_whats_new>
                        <support_url>http://someurl.com</support_url>
                        <software_screenshots>
                            <software_screenshot display_target="iOS-3.5-in" position="1">

                            </software_screenshot>
                            <software_screenshot display_target="iOS-4-in" position="1">

                            </software_screenshot>
                        </software_screenshots>
                    </locale>
                </locales>
            </version>
        </versions>
        <products>
            <product>
                <territory>WW</territory>
                <cleared_for_sale>true</cleared_for_sale>
                <sales_start_date>2013-01-05</sales_start_date>
                <intervals>
                    <interval>
                        <start_date>2013-08-25</start_date>
                        <end_date>2014-09-01</end_date>
                        <wholesale_price_tier>5</wholesale_price_tier>
                    </interval>
                    <interval>
                        <start_date>2014-09-01</start_date>
                        <wholesale_price_tier>6</wholesale_price_tier>
                    </interval>
                </intervals>
                <allow_volume_discount>true</allow_volume_discount>
            </product>
        </products>
    </software_metadata>
</software>

Answer 1

This is because, xml in python is not auto aware of namespaces. We need to prefix every element in a tree with the namespace prefix for lookup.

    import xml.etree.ElementTree as ET

namespaces = {"pns" : "http://apple.com/itunes/importer"}
tree = ET.parse('metadataCopy.xml')
root = tree.getroot()

p = root.find(".//pns:intervals/pns:interval", namespaces=namespaces)

print p
for interval in root.iterfind(".//pns:intervals/pns:interval",namespaces=namespaces):
    start_date = interval.find('pns:start_date',namespaces=namespaces)
    end_date = interval.find('pns:end_date',namespaces=namespaces)
    st_text = end_text = None
    if start_date is not None:
        st_text = start_date.text
    if end_date is not None:
        end_text = end_date.text 
    print st_text, end_text

The xml file shared is not well formed XML. The last tag has to end with package tag. With this change done, programs produces:

<Element '{http://apple.com/itunes/importer}interval' at 0x178b350>
2013-08-25 2014-09-01
2014-09-01 None

If its possible to change the library, you can look for using lxml. lxml has a great support for working with namespaces. Check out the quick short tutorial here http://lxml.de/tutorial.html#namespaces