HDT Format

Read RDF HDT (Header Dictionary Triples) compact stores as subject/predicate/object records.

Overview

Property	Value
Format id	hdt
Class	HDTIterable
Extensions	.hdt
Read	Yes
Write	No
Extra	rdf (requires the hdt package)
Maturity	experimental

Record shape

{"subject": "...", "predicate": "...", "object": "..."}

Parameters

Parameter	Description
subject	Triple pattern filter (default "" = all)
predicate	Triple pattern filter
object	Triple pattern filter

Requires a filename path. Streaming via HDTDocument.search_triples().

Usage

from iterable import open_iterable

with open_iterable("graph.hdt", format="hdt") as source:
    for triple in source:
        print(triple["subject"], triple["predicate"], triple["object"])

with open_iterable(
    "graph.hdt",
    format="hdt",
    iterableargs={"predicate": "http://xmlns.com/foaf/0.1/name"},
) as source:
    for triple in source:
        print(triple["subject"], triple["object"])

Install the hdt package (see pip install iterabledata[rdf] for related RDF extras).

Error Handling

• Missing dependency: optional libraries raise ImportError with an install hint (pip install 'iterabledata[<extra>]' when an extra exists).
• Read-only: opening with mode="w" raises WriteNotSupportedError or ValueError.
• Bad or unsupported input: may raise ValueError, OSError, or library-specific errors.
• See Troubleshooting for decoding, detection, and engine issues.

See also

• N-Triples — line-oriented triples
• Turtle — RDF Turtle
• RDF/XML — RDF/XML
• Supported formats