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Turtle Format (RDF)

Description​

Turtle is a text-based format for representing RDF (Resource Description Framework) data. It's a human-readable serialization of RDF graphs. Turtle files represent RDF triples (subject-predicate-object) in a compact, readable format.

File Extensions​

  • .ttl - Turtle RDF files
  • .turtle - Turtle RDF files (alias)

Implementation Details​

Reading​

The Turtle implementation:

  • Uses rdflib library for parsing
  • Parses RDF triples from Turtle format
  • Groups triples by subject
  • Converts each subject to a dictionary with its properties
  • Supports optional subject/predicate filtering

Writing​

Writing support:

  • Serializes each record as RDF triples via rdflib
  • Uses subject or @id as the subject URI; other keys become predicates
  • Install with pip install iterabledata[rdf]

Key Features​

  • RDF format: Represents RDF data
  • Human-readable: More readable than RDF/XML
  • Triple grouping: Groups triples by subject
  • Nested data: Supports complex RDF structures
  • Filtering: Can filter by subject or predicate

Usage​

from iterable import open_iterable

# Basic reading
with open_iterable('data.ttl') as source:
    for row in source:
        print(row)  # Each row represents a subject with its properties

# Filter by subject
source = open_iterable('data.ttl', iterableargs={
    'subject': 'http://example.org/person1'
})

# Writing
with open_iterable('output.ttl', mode='w') as dest:
    dest.write({
        'subject': 'http://example.org/alice',
        'http://xmlns.com/foaf/0.1/name': 'Alice',
    })

Parameters​

  • subject (str): Optional - Filter by subject URI
  • predicate (str): Optional - Filter by predicate URI
  • encoding (str): File encoding (default: utf8)

Limitations​

  1. RDF extra: Requires pip install iterabledata[rdf] (rdflib)
  2. Memory usage: Entire RDF graph is loaded into memory
  3. RDF complexity: Complex RDF structures may be difficult to work with
  4. Triple grouping: Triples are grouped by subject, which may not match all use cases

Compression Support​

Turtle files can be compressed with all supported codecs:

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