Possible error in 'dive into Python' book, help!

[Ben Edwards (lists)]

I have been going through Dive into Python which up to now has been
excellent. I am now working through Chapter 9, XML Processing. I am 9
pages in (p182) in the 'Parsing XML section. The following code is
supposed to return the whole XML document (I have put ti at the end of
this email):

from xml.dom import minidom

xmldoc =
minidom.parse('/home/ben/diveintopython-5.4/py/kgp/binary.xml')
grammerNode = xmldoc.firstChi ld

print grammerNode.tox ml()

But it only returns:

<!DOCTYPE grammar
PUBLIC '-//diveintopython. org//DTD Kant Generator Pro v1.0//EN'
'kgp.dtd'>

The next line is then

grammerNode.chi ldNodes

And it returns an empty tuples;(

Kind of stuck here as I don't really want to continue. Has anyone any
idea what is going on?

Ben

binary.xml

<?xml version="1.0"?>
<!DOCTYPE grammar PUBLIC "-//diveintopython. org//DTD Kant Generator Pro
v1.0//EN" "kgp.dtd">
<grammar>
<ref id="bit">
<p>0</p>
<p>1</p>
</ref>
<ref id="byte">
<p><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref
id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref
id="bit"/></p>
</ref>
</grammar>

[Sion Arrowsmith]

Re: Possible error in 'dive into Python' book, help!

In article <mailman.8658.1 154093256.27775 .python-list@python.org >,
Ben Edwards (lists) <lists@videonet work.orgwrote:

>I have been going through Dive into Python which up to now has been
>excellent. I am now working through Chapter 9, XML Processing. I am 9
>pages in (p182) in the 'Parsing XML section. The following code is
>supposed to return the whole XML document (I have put ti at the end of
>this email):
>
>from xml.dom import minidom
>
>xmldoc =
>minidom.parse( '/home/ben/diveintopython-5.4/py/kgp/binary.xml')
>grammerNode = xmldoc.firstChi ld
>
>print grammerNode.tox ml()
>
>But it only returns:
>
><!DOCTYPE grammar
PUBLIC '-//diveintopython. org//DTD Kant Generator Pro v1.0//EN'
'kgp.dtd'>
>
>The next line is then
>
>grammerNode.ch ildNodes
>
>And it returns an empty tuples;(
>
>Kind of stuck here as I don't really want to continue. Has anyone any
>idea what is going on?

OK, your xmldoc has two child nodes. The first is the <!DOCTYPE ... >
you're getting above. Which of course doesn't have any children, so
grammarNode.chi ldNodes is naturally empty. The <grammareleme nt is
the *second* child of the xmldoc, so of course isn't xmldoc.firstChi ld.
Probably what you want is:

grammarNode = xmldoc.document Element

Dive Into Python's assertion that "A Document always has only one
child node, the root element of the XML document" looks a little
off from where I'm standing:

>>print xmldoc.toxml()

<?xml version="1.0" ?>
<!DOCTYPE grammar
PUBLIC '-//diveintopython. org//DTD Kant Generator Pro v1.0//EN' 'kgp.dtd'>
<grammar>
<ref id="bit">
<p>0</p>
<p>1</p>
</ref>
<ref id="byte">
<p><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/><xref id="bit"/></p>
</ref>
</grammar>

>>xmldoc.childN odes

[<xml.dom.minido m.DocumentType instance at 0x4053640c>, <DOM Element: grammar at 0x40536f0c>]

>>>

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