Mailman 3 January 2010 - lxml - The Python XML Toolkit

[lxml-dev] lxml has its page on launchpad
by Stefan Behnel 11 Apr '23

11 Apr '23

Hi all, I added the lxml project to launchpad, the Ubuntu Bug-Tracker. It also has a FAQ engine and a couple of other goodies. https://launchpad.net/lxml It's easy to sign up for launchpad, BTW, no 90%-footnotes-contract. Have fun, Stefan

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[lxml-dev] Checking whether a node is a comment/element
by Geoffrey Sneddon 10 Apr '23

10 Apr '23

Hi, What's the best way to check whether a given node is a comment or an element? For the former, I'm currently using isinstance(node, etree._Comment), which is rather obviously sub-optimal. -- Geoffrey Sneddon <http://gsnedders.com/>

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[lxml-dev] Reparenting a node
by Lawrence Oluyede 30 Jan '23

30 Jan '23

I have a doc A and a doc B, I'd like to put a node extracted from A in the document B but I always get a ValueError: ValueError: Element is not a child of this node. I didn't find any "setparent" in the API. How can I do this? -- Lawrence, oluyede.org - neropercaso.it "It is difficult to get a man to understand something when his salary depends on not understanding it" - Upton Sinclair

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[lxml-dev] lxml 2.0.5 released
by Stefan Behnel 11 Jan '23

11 Jan '23

Hi all, lxml 2.0.5 is on PyPI. This is a bug-fix-only release of the stable 2.0 series. Have fun, Stefan 2.0.5 (2008-05-01) Bugs fixed * Resolving to a filename in custom resolvers didn't work. * lxml did not honour libxslt's second error state "STOPPED", which let some XSLT errors pass silently. * Memory leak in Schematron with libxml2 >= 2.6.31.

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[lxml-dev] Building LXML Trunk
by Sidnei da Silva 31 Aug '22

31 Aug '22

Hi, I've tried to build lxml from trunk today, on Win32. Got the following error: src\lxml\etree.c(880) : error C2059: syntax error : ')' src\lxml\etree.c(881) : error C2059: syntax error : ')' src\lxml\etree.c(882) : error C2059: syntax error : ')' src\lxml\etree.c(883) : error C2059: syntax error : ')' Any clue? Smells like a Pyrex issue? -- Sidnei da Silva Enfold Systems http://enfoldsystems.com Fax +1 832 201 8856 Office +1 713 942 2377 Ext 214

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[lxml-dev] confusing xpath performance characteristics
by jholg＠gmx.de 24 Aug '12

24 Aug '12

Hi, I ran into some performance characteristics of lxml/libxml2 xpath that I find rather confusing: I try to find the @type attribute of a certain element in an XML Schema (which contains lots of complexType definitions with lots of elements in them; unfortunately I can't post the schema): >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('NDM.xsd').getroot(); xpath = etree.XPath('//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.095885038375854492, 0.096823930740356445, 0.096174955368041992] So I think I'm being smart and give a little more path information - reckoning that this should *improve* performance: >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.1770780086517334, 0.1775970458984375, 0.17748594284057617] Hm. Performance degrades slightly. I'm adding even more of the path to where my desired elements live in the schema: >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('xsd/NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema/xs:complexType//xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [103.79744100570679, 103.83671712875366, 103.61817717552185] What??? >>> timeit.Timer(stmt="""xpath(schema)""", setup="""from lxml import etree, objectify; schema=etree.parse('/ae/data/pydev/hjoukl/NDM/SVN_CO/TRUNK/ndm/reference/xsd/NDM.xsd').getroot(); xpath = etree.XPath('/xs:schema/xs:complexType/*/xs:element[@name="equity"]/@type', namespaces={'xs': 'http://www.w3.org/2001/XMLSchema'})""").repeat(number=10) [0.044407129287719727, 0.044126987457275391, 0.044229030609130859] >>> Ok, this version's better than my naive approach, which seems logical to me. But why would '/xs:schema/xs:complexType//xs:element[@name="equity"]/@type' perform drastically slower than '/xs:schema/xs:complexType//xs:element[@name="equity"]/@type' ? libxml2 problem? Running the same xpaths in Oxygen I don't notice performance differences (can't profile this). Holger -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01

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[lxml-dev] Building an ESI tag with lxml
by Martin Aspeli 09 Feb '10

09 Feb '10

Hi, I'm trying to use lxml to conditionally insert an <esi:include /> tag into an HTML document. The document is parsed with the HTML parser and manipulated in various ways. At one point, I search for a node ('placeholder') and want to replace it with something that renders to: <esi:include src="http://..." /> The code I used looks like this: nsmap = {'esi': 'http://www.edge-delivery.org/esi/1.0'} root.nsmap.update(nsmap) # root is the <html /> element esiNode = etree.Element("{%s}include" % nsmap['esi'], nsmap=nsmap) esiNode.set('src', url) placeholder.addnext(esiNode) # placeholder is later removed There are two problems with this: - The xmlns:esi ends up on the <esi:include /> tag instead of the HTML root. Varnish doesn't like this apparently. - The <esi:include /> tag is not self-closing when rendered with the html.tostring (using etree.tostring is not really an option as other things are going on which want html rendering). Varnish likes this even less. Thus: <esi:include src="http://..." xmlns:esi="http://www.edge-delivery.org/esi/1.0"></esi:include> What can I do to push the namespace declaration up to the top node ('root') and make the tag self-closing? Martin -- Author of `Professional Plone Development`, a book for developers who want to work with Plone. See http://martinaspeli.net/plone-book

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[lxml-dev] ElementTree 1.3a xpath position broken?
by Richard Baron Penman 02 Feb '10

02 Feb '10

hello, I am after xpath support for an application running on Google App Engine, which unfortunately rules out lxml. According to this document (http://effbot.org/zone/element-xpath.htm) the development version of ElementTree 1.3a has additional support for xpath, which covers my use cases. >From my tests I found attributes and child nodes work: >>> from elementtree import ElementTree >>> tree = ElementTree.fromstring('<a><b></b><b><c class="test"></c></b></a>') >>> print list(tree.findall('.//*[@class="test"]')) [<Element 'c' at b7caa0cc>] >>> print list(tree.findall('.//b[c]')) [<Element 'b' at b7caa08c>] However tag positions appear to be broken: >>> print list(tree.findall('.//b[1]')) # should return b element [] Have I missed something? Suggestions? regards, Richard

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[lxml-dev] exslt functions in xpath expressions
by Dirk Rothe 01 Feb '10

01 Feb '10

During XPath Evaluations in XSL-Transformations it's possible to use Stuff from http://www.exslt.org/ (so [5] does indeed match the <a> element). During XPath Evaluations its only possible to use standard XPath/XSLT Functions. Is there a chance to enable the functions from exslt for lxml XPath evaluations as well? ========================================================= In [1]: from lxml import etree In [2]: from StringIO import StringIO In [3]: tree = etree.parse(StringIO('<a b="12"/>')) In [4]: print tree.xpath('/a[@b=concat("1","2")]') [<Element a at 2dbfbd0>] In [5]: print tree.xpath('/a[@b=str:split("12 34")]') [] ========================================================= --dirk

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[lxml-dev] Extending //r/text()
by Mateusz Korniak 29 Jan '10

29 Jan '10

Hi ! I am using lxml and find it really great ! Is it possible to extend like http://codespeak.net/lxml/extensions.html functions which are similar to //r/text() ? Although I have defined "testf" ns = lxml.etree.FunctionNamespace(None) ns['testf'] = testf from running: res = test_root.xpath("//r[testf()]") res = test_root.xpath("//r/text()") res = test_root.xpath("//r/testf()") I get: lxml.etree.XPathEvalError: Invalid expression when executing "//r/testf()" Thanks in advance and regards ! -- Mateusz Korniak

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