Re: [Tutor] A somewhat easier way to parse XML

[Kent Johnson]

Kent Johnson wrote:
On Jan 19, 2005, at 03:58, David Rock wrote:
    Indeed. The problem is, even if I know what I'm looking for, the  
problem remains that given the following document,

<foo>
    <bar>baz</bar>
</foo>
    If I want to get "baz", the command is ...

I'll try to find the time to write up a full example using ElementTree, 
Amara and dom4j. Meanwhile see http://www.oreillynet.com/pub/wlg/6225 
and http://www.oreillynet.com/pub/wlg/6239

OK, here is code to print 'baz' from a simple XML string using three different XML toolkits. (I 
added another level to the XML to make it a little more challenging.)

This is pretty much a tie - it's three lines of code in each toolkit. The main difference is between 
the XPath access used by ElementTree and dom4j and the attribute access used by amara. Personally I 
find dom4j's full XPath support to be very handy - it essentially gives you a query engine built in 
to your data model. But it is a matter of taste, and amara has XPath support also.

I put each example inside 'except ImportError' so I could have them all in one file - it's not 
something you would normally do. The ElementTree and amara examples are for CPython; the dom4j 
example is for Jython.

Of course you need the corresponding toolkit to be correctly installed...
Kent
docText = '''
<doc>
    <foo>
        <bar>baz</bar>
    </foo>
</doc>
'''
# ElementTree
try:
    from elementtree import ElementTree
    doc = ElementTree.XML(docText)
    # Note: doc represents the top-level ('doc') element
    print 'ElementTree'
    print doc.findtext('foo/bar')
except ImportError:
    print 'No ElementTree'
print
# amara
try:
    from amara import binderytools
    root = binderytools.bind_string(docText)
    # root is the 'root' element - the parent of the 'doc' element
    print 'amara'
    print root.doc.foo.bar
except ImportError:
    print 'No amara'
print
# dom4j
try:
    import org.dom4j as dom
    root = dom.DocumentHelper.parseText(docText)
    print 'dom4j'
    print root.valueOf('doc/foo/bar')
except ImportError:
    print 'No dom4j'
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