saving an 'lxml.etree._ElementTree' object

Question

I've spent the last couple of days getting to grips with the basics of lxml; in particular using lxml.html to parse websites and create an ElementTree of the content. Ideally, I want to save the returned ElementTree so that I can load it up and experiment with it, without having to parse the website every time I modify my script. I assumed that pickling would be the way to go, however I'm now beginning to wonder. Although I am able to retrieve an ElementTree object after pickling...

type(myObject) 

returns

<class 'lxml.etree._ElementTree'>

the object itself appears to be 'empty', since none of the subsequent method/attribute calls I make on it yield any output.

My guess is that pickling isn't appropriate here, but can anyone suggest an alternative?

(In case it matters, the above is happening in: python3.2, lxml 2.3.2, snow-leopard))

Answer 1

lxml is a C library - libxml to be precise - and the object probably don't support python pickling or any other kind of serialization - except serializing them to XML.

So you'll either have to keep them in memory, or re-parse the XML fragments you need, I assume.