DotNetRDF - List all ontology classes

Question

How can I enumerate all classess defined in ontology using DotNetRDF? I load ontology to start with and then need a way to get (enumerate) all classes. To load the ontology:

Dim g As New OntologyGraph
FileLoader.Load(g, strURI)
Now, I would need something like dim enmClasses as OntologyClasses = g.GetAllClasses(g).

I use VB, but have no problems if you use C# to help me with this :)

Accepted Answer

3

Assuming all your classes are defined as belonging to some common type like rdfs:Class or owl:Class you can do the following with an OntologyGraph:

//This gets the class for things which are declared to be a class
OntologyClass classOfClasses = g.CreateOntologyClass(g.CreateUriNode("owl:Class"));

//This iterates over the things that are a class
foreach (OntologyResource class in classOfClasses.Instances)
{
  //Do what you want with the class
}

We'll look at adding a Classes property/method to the OntologyGraph in a future release. And adding some easier casting between OntologyResource and OntologyClass

link

answered 11 Dec '12, 20:09

Rob Vesse ♦
11.8k●6●15
accept rate: 28%

Notes for improvements filed as CORE-293 (http://dotnetrdf.org/tracker/Issues/IssueDetail.aspx?id=293) - please register and add further comments if there are other missing features you'd like to see

(11 Dec '12, 20:13) Rob Vesse ♦

See https://bitbucket.org/dotnetrdf/dotnetrdf/commits/1142f2971eefb8fffb7143153015e960e22b8d00 for some new methods and properties already added, the code there should provide alternative answers to your question

(12 Dec '12, 00:44) Rob Vesse ♦

DotNetRDF - List all ontology classes

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