Sayth Renshaw wrote:
> I am following John Shipmans example from
> http://infohost.nmt.edu/~shipman/soft/pylxml/web/Element-getchildren.html
>
>>>> xml = '''<corral><horse n="2"/><cow n="17"/>
> ... <cowboy n="2"/></corral>'''
>>>> pen = etree.fromstring(xml)
>>>> penContents = pen.getchildren()
>>>> for content in penContents:
> ... print "%-10s %3s" % (content.tag, content.get("n", "0"))
> ...
> horse 2
> cow 17
> cowboy 2
>>>>
>
> If I make one minor modification to the xml and change an n to an m as in
> my example below the getchildren will return none for none matches, how
> can I ignore nones?
>
> In [2]: from lxml import etree
>
> In [3]: xml = '''<corral><horse n="2"/><cow m="17"/> <cowboy
> n="2"/></corral>'''
>
> In [4]: pen =etree.fromstring(xml)
>
> In [5]: pencontents = pen.getchildren()
>
> In [6]: for content in pencontents:
> ...: print(content.get('n'))
> 2
> None
> 2
>
> Because
> In [17]: for content in pencontents:
> ....: if content is not None:
> ....: print(content.get('n'))
>
> Sayth
The obvious fix would be to check for None in the right place:
>>> for content in pen.getchildren():
... n = content.get("n")
... if n is not None:
... print(content.tag, n)
...
horse 2
cowboy 2
Another option would be to select only children that have an "n" attribute
using xpath:
>>> for content in pen.xpath("/corral/*[@n]"):
... print(content.tag, content.get("n"))
...
horse 2
cowboy 2
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