On 5/31/06, Miles Waller <[EMAIL PROTECTED]> wrote: > Hi, > > I'm hoping someone can help with me with this question about rdflib. > Apologies in advance as i'm new to rdflib > (and to rdf a bit too) and this might be a newbie question. > > I have some code which I am using to construct an rdf sequence. I call > 'addItemToSequence' several times > to build up the sequence, having set up the graph elsewhere. > > ns_client_site1_url = "http://example.com/ns/client-site1#"; > ns_client_site1 = Namespace(ns_client_site1_url) > site = ns_client_site1 > > def addItemToSequence(source_id, target_id) > g.add( (site[source_uid], RDF.Seq, URIRef('children_of_%s' % > source_uid) ) ) > s = Seq( g, URIRef('children_of_%s' % source_uid) ) > g.add( (URIRef('children_of_%s' % source_uid), RDF.li, > site[target_uid]) ) > > I get the following rdf out of it: > > <rdf:RDF > xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'> > <rdf:Description rdf:about="http://example.com/ns/client-site1#124";> > <rdf:Seq> > <rdf:Description rdf:about="children_of_124"> > <rdf:li rdf:resource="http://example.com/ns/client-site1#157"/> > <rdf:li rdf:resource="http://example.com/ns/client-site1#151"/> > > </rdf:Description> > </rdf:Seq> > </rdf:Description> > </rdf:RDF> > > The intent is to produce the rdf required to describe a simple, > hierarchical site map as used by a website, > which i can then query. In the example, the resources and > target_uid/source_uid represent the unique ids > of the pages that are related. > > Now, my questions are: > > - have i created a sequence correctly here?
No, the sequence wasn't properly created. The rdf:li is RDF/XML synactic short cut to using rdf:_1,rdf:_2,etc.. explicitely. See: http://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-list-elements Also the rdf:Seq is mean't to be the object of an rdf:type statement (identifiying the resource as a sequence) - you are using it incorrectly. Finally, rdflib.Graph.Seq is a convenience class for iterating over an rdf:Seq, not creating one (thought it would probably be useful to support creating a rdf:Seq as well). What (I think) you want is: ns_client_site1_url = "http://example.com/ns/client-site1#"; ns_client_site1 = Namespace(ns_client_site1_url) site = ns_client_site1 def addItemToSequenceAtOnce(source_id, target_ids) for target_id in target_ids: g.add( (URIRef('children_of_%s' % source_id), RDFNS['_'+target_ids.index(target_id)], site[target_id]) ) def addItemToSequence(source_id, target_id) s = Seq( g, URIRef('children_of_%s' % source_id) ) nextIndex = len(s) + 1 g.add( (URIRef('children_of_%s' % source_id), RDFNS['_'+nextIndex], site[target_id]) ) g.add((URIRef('children_of_%s' % source_uid),RDF.type,RDF.Seq) addItemToSequence(URIRef('children_of_%s' % source_uid),target_id_1) addItemToSequence(URIRef('children_of_%s' % source_uid),target_id_2) ... or ... addItemToSequenceAtOnce(URIRef('children_of_%s' % source_uid),[target_id_1,target_id_2]) > i.e. am i _always_ going to > get the items back in the same order, or > do i just get them back in this order because of a quirk of > python/rdflib. You should always get them back in the same order due to the rdf:_1,rdf:_2, etc..member properties. Order is inherent with those properties. > > - finally, if i want to change the order of items in the sequence, how > should this be done? delete all the items > and add them again in the right order? I think that would be your only option > do sequences provide any help to > 'promote' items at all? should they? I'm not sure what you mean by promote. _______________________________________________ Dev mailing list [email protected] http://rdflib.net/mailman/listinfo/dev
