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RDF/XML Format

Description​

RDF/XML is an XML-based serialization format for RDF (Resource Description Framework) data. It represents RDF triples (subject-predicate-object) in XML format. RDF/XML is one of the standard RDF serialization formats.

File Extensions​

  • .rdf - RDF/XML files
  • .rdf.xml - RDF/XML files (alias)

Implementation Details​

Reading​

The RDF/XML implementation:

  • Uses lxml library for XML parsing
  • Parses RDF Description elements
  • Extracts RDF triples (subject-predicate-object)
  • Groups triples by subject
  • Converts RDF data to dictionaries

Writing​

Writing support:

  • Writes RDF Description elements (simplified RDF/XML)
  • Triple-oriented records use subject plus a triples list

Key Features​

  • RDF format: Represents RDF data in XML
  • Triple extraction: Extracts RDF triples
  • Subject grouping: Groups triples by subject
  • Nested data: Supports complex RDF structures
  • XML parsing: Uses XML parsing for RDF data

Usage​

from iterable import open_iterable

# Basic reading
with open_iterable('data.rdf') as source:
    for row in source:
        print(row)  # Contains RDF triples grouped by subject

# Writing
with open_iterable('output.rdf', mode='w') as dest:
    dest.write({'subject': 'http://example.org/alice', 'name': 'Alice'})

Parameters​

  • encoding (str): File encoding (default: utf8)

Limitations​

  1. lxml dependency: Requires lxml package
  2. Memory usage: Entire RDF graph may be loaded into memory
  3. RDF complexity: Complex RDF structures may be difficult to work with
  4. XML complexity: Complex XML namespaces may require manual handling

Compression Support​

RDF/XML files can be compressed with all supported codecs:

  • GZip (.rdf.gz)
  • BZip2 (.rdf.bz2)
  • LZMA (.rdf.xz)
  • LZ4 (.rdf.lz4)
  • ZIP (.rdf.zip)
  • Brotli (.rdf.br)
  • ZStandard (.rdf.zst)

Use Cases​

  • Semantic web: Working with semantic web data
  • Linked data: Processing linked data
  • Knowledge graphs: Building and querying knowledge graphs
  • Metadata: Working with RDF metadata

Error Handling​

  • Missing dependency: optional libraries raise ImportError with an install hint (pip install 'iterabledata[<extra>]' when an extra exists).
  • Write mode: read-only formats raise WriteNotSupportedError or ValueError when opened with mode="w".
  • Bad or unsupported input: may raise ValueError, OSError, or library-specific errors.
  • See Troubleshooting for decoding, detection, and engine issues.
  • Turtle - More readable RDF format
  • N-Triples - Simpler RDF format
  • N-Quads - N-Triples with graph context
  • XML - Base XML format