Difference between revisions of "Lab: RDF programming with RDFlib"

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* Basic RDF graph programming with RDFlib.
 
* Basic RDF graph programming with RDFlib.
 
* Simple reading/writing from/to file.
 
* Simple reading/writing from/to file.
* Simple looping trough graph
+
* Simple looping through graph
* Setting up groups for the group project
 
  
 +
==Classes/interfaces==
 +
from rdflib import Graph, Namespace, URIRef, BNode, Literal
  
==Classes/interfaces==
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from rdflib.namespace import RDF, FOAF, XSD
import [https://rdflib.readthedocs.io/en/stable/py-modindex.html rdflib]:
+
 
*Graph (add, remove, serialize, parse)
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from rdflib.collection import Collection
*Namespace
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*URIRef
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*Literal
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Methods:
*Bnode
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Graph - add(), remove(), triples(), serialize(), parse(), bind()
*RDF, FOAF, XSD
 
  
 
==Tasks==
 
==Tasks==
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Denmark and Sweden. Cade knows Emma. They met in Paris in August
 
Denmark and Sweden. Cade knows Emma. They met in Paris in August
 
2014."
 
2014."
(Make up your own URIs when you need to (like "http://example.org/"), or even better: use terms
 
you know from vocabularies such as FOAF and RDF.
 
  
Create a graph in RDFlib with triples corresponding to the text above.
 
  
Write (serialize) out your graph to the console in the following formats: "turtle",
+
Create a graph in RDFlib with triples corresponding to the text above. Build on the graph from lab 1. Use your own URIs when you need to (like "http://example.org/"), but try to use terms from vocabularies such as FOAF, RDF, XSD, and others.
"n3", "nt", "xml". How do they differ? What is the default?
 
  
Write your graph to a file.
+
Write out your graph to the console. This seems to be the cleanest way of printing the graph to me:
Here is an example of writing a to a file in turtle format: g.serialize(destination="triples.txt", format="turtle")
+
print(g.serialize(format="turtle"))
 +
But try all the following formats: "turtle", "n3", "nt", "json-ld", "xml". How do they differ? What is the default?
  
 +
Write your graph to a file. To do this, you can simply use the location parameter e.g: g.serialize(destination="triples.txt", format="turtle").
  
Edit the file so that Cade has also visited Germany and so that Emma is 26 years old.  
+
Look at the file and edit it so that Cade has also visited Germany and so that Emma is 26 years old.  
  
 
Create a new program that reads your graph in again from the file and
 
Create a new program that reads your graph in again from the file and
writes it to the console. Check that your new data is there!
+
writes it to the console. e.g g.parse(location="triples.txt", format="turtle")
 +
Check that your new data is there!
  
 
Continuing with either your first or second program, write a loop that
 
Continuing with either your first or second program, write a loop that
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Change the loop so that (a) it only loops through triples about
 
Change the loop so that (a) it only loops through triples about
 
Emma (b) it only loops through triples involving the names of
 
Emma (b) it only loops through triples involving the names of
people.
+
people.  
  
 
Remove all triples about Mary using graph.remove(). (triples of Mary are from lab 1)
 
Remove all triples about Mary using graph.remove(). (triples of Mary are from lab 1)
  
==If you have more time...==
+
==Useful Links==
  
Below are four lines of comma-separated values (csv - five lines with
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[https://rdflib.readthedocs.io/en/stable/index.html rdflib documentation]:
the headers) that could have been saved from a spreadsheet. Copy them
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* [https://rdflib.readthedocs.io/en/stable/intro_to_creating_rdf.html Creating Triples]
into a file and write a program with a loop that reads each line from that file (except
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* [https://rdflib.readthedocs.io/en/stable/intro_to_graphs.html Navigating Graphs]
the initial header line) and adds it to your graph as triples:
+
* [https://rdflib.readthedocs.io/en/stable/intro_to_parsing.html Parsing]
 
 
  "Name","Gender","Country","Town","Expertise","Interests"
 
  "Regina Catherine Hall","F","Great Britain","Manchester","Ecology, zoology","Football, music travelling"
 
  "Achille Blaise","M","France","Nancy","","Chess, computer games"
 
  "Nyarai Awotwi Ihejirika","F","Kenya","Nairobi","Computers, semantic networks","Hiking, botany"
 
  "Xun He Zhang","M","China","Chengdu","Internet, mathematics, logistics","Dancing, music, trombone"
 
 
 
In the resulting graph, delete all information about Achille.
 
 
 
==Useful Links==
 
  
* [https://rdflib.readthedocs.io/en/stable/index.html rdflib documentation]:
+
[https://wiki.uib.no/info216/index.php/File:S02-RDF-9.pdf Lecture Notes]

Latest revision as of 15:53, 4 February 2022

Lab 2: RDF programming with RDFlib

Topics

  • Basic RDF graph programming with RDFlib.
  • Simple reading/writing from/to file.
  • Simple looping through graph

Classes/interfaces

from rdflib import Graph, Namespace, URIRef, BNode, Literal

from rdflib.namespace import RDF, FOAF, XSD

from rdflib.collection import Collection


Methods: Graph - add(), remove(), triples(), serialize(), parse(), bind()

Tasks

Consider the following situation: "Cade lives in 1516 Henry Street, Berkeley, California 94709, USA. He has a B.Sc. in biology from the University of California, Berkeley from 2011. His interests include birds, ecology, the environment, photography and travelling. He has visited Canada and France. Emma Dominguez lives in Carrer de la Guardia Civil 20, 46020 Valencia, Spain. She has a M.Sc. in chemistry from the University of Valencia from 2015. Her areas of expertise include waste management, toxic waste, air pollution. Her interests include bike riding, music and travelling. She has visited Portugal, Italy, France, Germany, Denmark and Sweden. Cade knows Emma. They met in Paris in August 2014."


Create a graph in RDFlib with triples corresponding to the text above. Build on the graph from lab 1. Use your own URIs when you need to (like "http://example.org/"), but try to use terms from vocabularies such as FOAF, RDF, XSD, and others.

Write out your graph to the console. This seems to be the cleanest way of printing the graph to me: print(g.serialize(format="turtle")) But try all the following formats: "turtle", "n3", "nt", "json-ld", "xml". How do they differ? What is the default?

Write your graph to a file. To do this, you can simply use the location parameter e.g: g.serialize(destination="triples.txt", format="turtle").

Look at the file and edit it so that Cade has also visited Germany and so that Emma is 26 years old.

Create a new program that reads your graph in again from the file and writes it to the console. e.g g.parse(location="triples.txt", format="turtle") Check that your new data is there!

Continuing with either your first or second program, write a loop that goes through all the triples in the graph and prints them to the console.

Change the loop so that (a) it only loops through triples about Emma (b) it only loops through triples involving the names of people.

Remove all triples about Mary using graph.remove(). (triples of Mary are from lab 1)

Useful Links

rdflib documentation:

Lecture Notes