RDFLib/rdflib

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Iwan Aucamp

@aucampia

There is about 10 seconds lag between matrix and gitter though

remi.chateauneu

@remi.chateauneu:matrix.org

[m]

white_gecko

@white_gecko:matrix.org

[m]

Which matrix room did you bridge? Am I in the gitter room or in the native matrix room?

Iwan Aucamp

@aucampia

This is the gitter room, not the native matrix room

noting is bridged other than through automatic bridges

white_gecko

@white_gecko:matrix.org

[m]

Ah ok, I understand.

Avy Faingezicht

@avyfain

Does anyone have code snippets/patterns to share on how to properly deal with reification in rdflib? I'm planning to use python + rdflib to create a graph from a few sources, and I am planning to use reification for provenance (learned fact X from source Y) as well as for temporality (X worked at Y since Z). I found it odd that there was nothing about that in the docs

Iwan Aucamp

@aucampia

Presumably this is not RDF* reificiation?

If it is not RDF* then there is no specific language support

or library support

Well there is no specific RDF* support either

I will try make an example though on using RDF 1.1 recommendation for reification (i.e. rdf:Statement IIRC)

CC: @avyfain

Iwan Aucamp

@aucampia

will only look at it tonight though

4 replies

Avy Faingezicht

@avyfain

Thanks @aucampia! I am starting from scratch here, so if RDF* was available then I'd probably go with that since it's the next big standard, but just good old RDF 1.1 would be ok

import rdflib
from rdflib.namespace import RDF

lit2019 = rdflib.Literal('2019-01-01', datatype=rdflib.XSD.date)
lit2020 = rdflib.Literal('2020-01-01', datatype=rdflib.XSD.date)

bob = rdflib.URIRef("http://example.org/people/Bob")
google = rdflib.URIRef("http://example.org/companies/Google")
workedAt = rdflib.URIRef("http://example.org/stuff/0.1/workedAt")
startTime = rdflib.URIRef("http://example.org/stuff/0.1/startTime")
endTime = rdflib.URIRef("http://example.org/stuff/0.1/endTime")

g = rdflib.Graph()

position = (bob, workedAt, google)
reified_position = (position, RDF.type, RDF.Statement)

g.add(position)
g.add(reified_position)
g.add((reified_position, startTime, lit2019))

I tried running this but can't add that second triple, I guess I'd have to make it a BNode?

Iwan Aucamp

@aucampia

@avyfain https://gist.github.com/aucampia/11fb776325b4a1da053e2f6099895228

hope that helps

Iwan Aucamp

@aucampia

I updated it to schema.org instead

will maybe share it on stackoverflow also

though not sure it is extremely idomatic

Iwan Aucamp

@aucampia

An example with http://www.ontotext.com/proton/protontop.html#Statement may be more idiomatic

Avy Faingezicht

@avyfain

That's super helpful, yeah! Thanks a lot Iwan! I'm pretty new to the semantic web side of things, so still picking up on the right patterns/namespaces/etc. I'll play around with this some more and maybe after a bit I can share where I end up

Iwan Aucamp

@aucampia

Ask if you need more help, will help when I can

Always glad to have more people using it :)

Another great place to ask for help in general is https://gitter.im/linkeddata/chat - but that is just general semantic web and not rdflib specific

joylix

@joylix

Does rdflib support RDF-star and SPARQL-star now?

Iwan Aucamp

@aucampia

@joylix not yet AFAIK see RDFLib/rdflib#955

Avy Faingezicht

@avyfain

Is there a way to set up a default language for a graph, just like there's the default context?

Iwan Aucamp

@aucampia

Like the default language for string literals?

I don't think there is a built in way to do that

Avy Faingezicht

@avyfain

Hmm bummer. Yeah, that's what I was thinking. Partly because if they are null they aren't unique when using the sqlalchemy backend.

rpgoldman

@rpgoldman

Is there a way to add a prefix definition for : in RDFLib? g.bind("", ns) does not seem to work.

When I normalize a URI with that binding, I get default1:foobar for :foobar

Avy Faingezicht

@avyfain

Anyone here has experience working with large datasets in rdflib-sqlalchemy with psql as a backend? any advice on reducing latencies at read/write time?

Iwan Aucamp

@aucampia

I have not used it, but I guess the best advice I can give is to try and isolate where the latency is coming from

2 replies

rpgoldman

@rpgoldman

Wanted to ask a question about rdflab.extras.infixowl : I don't see how to enter a datatype restriction (e.g., the numericalUnit only owl:real [>= 200 ] Anyone know if this is possible?

2 replies

Iwan Aucamp

@aucampia

Hope Nick knows we appreciate all the work he puts into this

Can imagine it must feel a bit thankless

But I think it is invaluable

white_gecko

@white_gecko:matrix.org

[m]

I have forwarded it to him.

Iwan Aucamp

@aucampia

thanks :)

white_gecko

@white_gecko:matrix.org

[m]

Thank you, for giving room to such important things in live :-)

Iwan Aucamp

@aucampia

If anyone has time for a review: RDFLib/rdflib#1452 - Migrate from nosetest to pytest

Iwan Aucamp

@aucampia

Need more reviewers :/

Robert Alexander

@rjalexa

Dear friends, medical doctor here trying to model human medicines. I generate a .ttl file which works well but I need to add the following line manually everytime: http://isagog.com/dataset/aifa rdf:type owl:Ontology ;
owl:imports http://isagog.com/ontologies/pharma .
Is there a way to use RDFLib in such a way that it will add that when serializing/writing the file? Thank you so much for this wonderful package.

Robert Alexander

@rjalexa

Nevermind, I overcame my brain freeze and found the solution :) Thanks to you all

Graham Higgins

@gjhiggins

@aucampia https://github.com/RDFLib/rdflib/actions ... Nice!

2 replies

greattang123

@greattang123

Dear rdflib manitainers,
I am a user of rdflib. When I use rdflib.Graph to parse one .nt file, the terminal output is
rdflib.exceptions.ParserError: Invalid line: http://dbpedia.org/resource/2015_African_Rugby_Under-19_Cup_Division_"A" .
While I remove the double quotations of ”A", i.e., "A" -> A，the program is OK. I want to know if there are other ways to parsing the .nt file rather than remove the double quotations of ”A".
Thanks a lot.
Yours Sincerely.

Appendix
Data{ <a:> http://www.w3.org/2002/07/owl#sameAs http://dbpedia.org/resource/2015_African_Rugby_Under-19_Cup_Division_"A" .}
Code{
from rdflib import Graph
g = Graph()
g.parse("./data/example.nt")
print(f"Graph g has {len(g)} statements.")
print(g.serialize(format="turtle"))
}

Graham Higgins

@gjhiggins

Looks like a problematic URL for dbpedia. With, or without the double qutoes, that dbpedia URL returns a “301 See other” and the relocate is https://dbpedia.org/resource/2015_African_Rugby_Under-19_Cup_Division_%22A%22- which itself fails to resolve. OTOH, wikipedia returns a corresponding redirect https://en.wikipedia.org/wiki/2015_African_Rugby_Under-19_Cup_Division_%22A%22 which is found. The dbpedia page is essentially blank, it has none of the info for that entry on wikipedia.

1 reply

Iwan Aucamp

@aucampia

@greattang123 I once had similar issues, and then what I did was basically to run urllib.parse.quoteon the bad URL first

1 reply

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