How to use the command 'rapper' (with examples)

The rapper command is part of the Raptor RDF Syntax Library and is used for parsing RDF (Resource Description Framework) documents. It provides various functionalities for converting RDF files from one syntax to another and counting the number of triples in a file.

Use case 1: Convert an RDF/XML document to Turtle

Code:

rapper -i rdfxml -o turtle path/to/file

Motivation: Converting an RDF/XML document to Turtle syntax can be useful for various reasons. RDF/XML is a complex and verbose format, while Turtle is a more human-readable and compact format. Turtle is also recommended for creating and editing RDF manually.

Explanation:

• rapper: The command itself.
• -i rdfxml: Sets the input syntax to RDF/XML.
• -o turtle: Sets the output syntax to Turtle.
• path/to/file: Specifies the path to the RDF/XML file to be converted.

Example output:

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

<http://example.org/john-doe> a foaf:Person ;
    foaf:name "John Doe" ;
    foaf:age 30 .

Use case 2: Count the number of triples in a Turtle file

Code:

rapper -i turtle -c path/to/file

Motivation: Knowing the number of triples in an RDF file can provide a sense of its complexity and scale. It can be useful for performance optimization or assessing the size of a dataset.

Explanation:

• rapper: The command itself.
• -i turtle: Sets the input syntax to Turtle.
• -c: Count the number of triples.
• path/to/file: Specifies the path to the Turtle file to be counted.

Example output:

123

Conclusion:

The rapper command is a versatile tool for working with RDF files. It allows users to convert between different RDF syntaxes and count the number of triples in a file. These use cases demonstrate its utility in transforming and analyzing RDF data.