First, thanks to everyone who responded. Figured I'd test all the
suggestions and provide a response to the list. Here goes ...
On Jun 25, 2009, at 7:38 PM, Nobody wrote:
Why do you need an ElementTree rather than an Element? XML(string)
returns
the root element, as if you had used et.parse(f).getroot(). You can
turn
this into an ElementTree with e.g. et.ElementTree(XML(string)).
I tried this:
et.ElementTree(XML(theXmlData))
and it did not work.
I had to modify it to this to get it to work:
et.ElementTree(et.XML(theXmlData))
formPostData = cgi.FieldStorage()
theXmlData = formPostData['theXml'].value
theXmlDataTree =
et
.parse
(makeThisUnicodeStringLookLikeAFileSoParseWillDealWithIt(theXmlData))
If you want to treat a string as a file, use StringIO.
I tried this:
import StringIO
theXmlDataTree = et.parse(StringIO.StringIO(theXmlData))
orderXml = theXmlDataTree.findall('purchase')
and it did work. StringIO converts the string into what looks like a
file so parse can process it as a file. Cool.
On Jun 25, 2009, at 7:47 PM, unayok wrote:
I'm not sure what you're expecting. It looks to me like things are
working okay:
My test script:
[snip]
I agree your code works.
When I tried:
theXmlDataTree = et.fromstring(theXmlData)
orderXml = theXmlDataTree.findall('purchase')
When I modified mine to programmatically look inside using the "for
element in theXmlDataTree" I was able to see the contents. The
debugger I am using does not offer me a window into the ElementTree
data and that was part of the problem. So yes, et.fromstring is
working correctly. It helps to have someone show me the missing step
needed to confirm the code works and the IDE does not.
On Jun 25, 2009, at 8:04 PM, Carl Banks wrote:
I believe you are misunderstanding something. et.XML and
et.fromstring return Elements, whereas et.parse returns an
ElementTree. These are two different things; however, both of them
"contain all the XML". In fact, an ElementTree (which is returned by
et.parse) is just a container for the root Element (returned by
et.fromstring)--and it adds no important functionality to the root
Element as far as I can tell.
Thank you for explaining the difference. I absolutely was
misunderstanding this.
Given an Element (as returned by et.XML or et.fromstring) you can pass
it to the ElementTree constructor to get an ElementTree instance. The
following line should give you something you can "play with":
theXmlDataTree = et.ElementTree(et.fromstring(theXmlData))
Yes this works.
On Jun 25, 2009, at 11:39 PM, Stefan Behnel wrote:
If you want to parse a document from a file or file-like object, use
parse(). Three use cases, three functions. The fourth use case of
parsing a
document from a string does not have its own function, because it is
trivial to write
tree = parse(BytesIO(some_byte_string))
:-) Trivial for someone familiar with the language. For a newbie like
me, that step was non-obvious.
If what you meant is actually parsing from a byte string, this is
easily
done using BytesIO(), or StringIO() in Py2.x (x<6).
Yes, thanks! Looks like BytesIO is a v.3.x enhancement. Looks like the
StringIO does what I need since all I'm doing is pulling the unicode
string into et.parse. Am guessing that either would work equally well.
theXmlDataTree =
et
.parse
(makeThisUnicodeStringLookLikeAFileSoParseWillDealWithIt(theXmlData))
This will not work because ET cannot parse from unicode strings
(unless
they only contain plain ASCII characters and you happen to be using
Python
2.x). lxml can parse from unicode strings, but it requires that the
XML
must not have an encoding declaration (which would render it non
well-formed). This is convenient for parsing HTML, it's less
convenient for
XML usually.
Right for my example, if the data is coming in as UTF-8 I believe I
can do:
theXmlDataTree = et.parse(StringIO.StringIO(theXmlData), encoding
='utf-8')
Again, as a newbie, thanks to everyone who took the time to respond.
Very helpful.
Kee
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