lxml - The Python XML Toolkit April 2010

lxml@python.org

16 participants
20 discussions

[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] Checking whether a node is a comment/element
by Geoffrey Sneddon 11 Jan '23

11 Jan '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/>

4 4

[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.

3 4

[lxml-dev] lxml has its page on launchpad
by Stefan Behnel 21 Sep '22

21 Sep '22

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

3 2

[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] installing lxml on MacOS
by Stephen Graham 18 May '10

18 May '10

I am trying to go down the learning curve on lxml. I tried to follow the install instructions to install lxml on my MacOS As root, I did: STATIC_DEPS=true easy_install lxml The install chugged away, but eventually failed: ... Undefined symbols for architecture i386: "_gzdirect", referenced from: ___xmlParserInputBufferCreateFilename in libxml2.a(xmlIO.o) ld: symbol(s) not found for architecture i386 collect2: ld returned 1 exit status Undefined symbols for architecture ppc: "_gzdirect", referenced from: ___xmlParserInputBufferCreateFilename in libxml2.a(xmlIO.o) ld: symbol(s) not found for architecture ppc collect2: ld returned 1 exit status lipo: can't open input file: /var/tmp//ccsmIZu8.out (No such file or directory) make[2]: *** [xmllint] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 Traceback (most recent call last): File "/usr/bin/easy_install", line 8, in <module> load_entry_point('setuptools==0.6c7', 'console_scripts', 'easy_install')() File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 1670, in main with_ei_usage(lambda: File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 1659, in with_ei_usage return f() File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 1674, in <lambda> distclass=DistributionWithoutHelpCommands, **kw File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/distutils/core.py", line 151, in setup dist.run_commands() File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/distutils/dist.py", line 974, in run_commands self.run_command(cmd) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/ python2.5/distutils/dist.py", line 994, in run_command cmd_obj.run() File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 211, in run self.easy_install(spec, not self.no_deps) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 446, in easy_install return self.install_item(spec, dist.location, tmpdir, deps) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 471, in install_item dists = self.install_eggs(spec, download, tmpdir) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 655, in install_eggs return self.build_and_install(setup_script, setup_base) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 930, in build_and_install self.run_setup(setup_script, setup_base, args) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/command/easy_install.py", line 919, in run_setup run_setup(setup_script, args) File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/sandbox.py", line 27, in run_setup lambda: execfile( File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/sandbox.py", line 63, in run return func() File "/System/Library/Frameworks/Python.framework/Versions/2.5/ Extras/lib/python/setuptools/sandbox.py", line 29, in <lambda> {'__file__':setup_script, '__name__':'__main__'} File "setup.py", line 119, in <module> File "/tmp/easy_install-XVh5wp/lxml-2.2.6/setupinfo.py", line 50, in ext_modules File "/tmp/easy_install-XVh5wp/lxml-2.2.6/buildlibxml.py", line 208, in build_libxml2xslt File "/tmp/easy_install-XVh5wp/lxml-2.2.6/buildlibxml.py", line 158, in call_subprocess Exception: Command "make" returned code 2 Any thing obvious jump out at anyone that I might have missed? thanks in advance sgg Steve Graham sgg(a)ci.uchicago.edu

5 16

[lxml-dev] examine XSD xml schema
by Michael Konietzny 03 May '10

03 May '10

Hello, I would like to examine a XSD schema in python. Currently I'm using lxml which is doing it's job very very well when it only has to validate a document against the schema. But, I want to know whats inside of the schema and access the elements in the lxml behavior. The schema: |<?xml version="1.0"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:include schemaLocation="worker_remote_base.xsd"/> <xsd:include schemaLocation="transactions_worker_responses.xsd"/> <xsd:include schemaLocation="transactions_worker_requests.xsd"/> </xsd:schema> | The lxml code to load the schema is (simplyfied): |xsd_file_handle= open( self._xsd_file, 'rb') xsd_text= xsd_file_handle.read() schema_document= etree.fromstring(xsd_text, base_url=xmlpath) xmlschema= etree.XMLSchema(schema_document) | I'm then able to use schema_document (which is etree._Element) to go through the schema as an XML document. But since etree.fromstring (at least it seams like that) expects a XML document the |xsd:include| elements are not processed. The problem is currently solved by parsing the first schema document, then load the include elements and then insert them one by one into the main document by hand: |BASE_URL= "/xml/" schema_document= etree.fromstring(xsd_text, base_url=BASE_URL) tree= schema_document.getroottree() schemas= [] for schemaChildin schema_document.iterchildren(): if schemaChild.tag.endswith("include"): try: h= open(os.path.join(BASE_URL, schemaChild.get("schemaLocation")), "r") s= etree.fromstring(h.read(), base_url=BASE_URL) schemas.append(s) except Exception as ex: print "failed to load schema: %s" % ex finally: h.close() # remove the<xsd:include ...> element self._schema_document.remove(schemaChild) for sin schemas: # inside<schema> for sChildin s: schema_document.append(sChild) | What I'm asking for is an idea how to solve the problem by using a more common way. I've already searched for other schema parsers in python but for now there was nothing that would fit in that case. Greetings, Michael

2 1

[lxml-dev] Adding internal DTD entities?
by Brad Smith 01 May '10

01 May '10

Hello all, First, thanks to those responsible for lxml, it has made processing xml in python an almost-fun experience! ;) I have only found one thing I need to be able to do, but of which I can't seem to find any examples. I have entities defined in a file that is shared by all of the files in a document (which are xi:include'ed into the main doc). Thus, I want each document to begin with something like: <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ <!ENTITY % common_entities SYSTEM "common.ent" > %common_entities; ]> The problem is that some of the files in the doc are auto-generated by a python/lxml pre-processing script, and I can't figure out how to have lxml insert that entity definition into the doctype declaration. Any suggestions here would be greatly appreciated. Thanks! --Brad

2 1

[lxml-dev] using xpath to grab and *modify* a sub-element?
by Daniel Robbins 29 Apr '10

29 Apr '10

Hi All, I am new to lxml, but so far it seems that xpath functions/methods return *copies* of a SubElement, and thus any modifications I make to the returned element does not affect the master element. This is quite fine for retrieving data, but what if I want to use xpath to find SubElements, that I then want to modify in some way, so that my changes are reflected in the master Element? Any short code snippet or link to an example would be appreciated. I've been searching but haven't found any yet. Thanks and Regards, -Daniel Robbins

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lxml - The Python XML Toolkit April 2010