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Forward index

A forward index is a data structure that maps each document to the terms, features, or fields it contains.

How 2 Manning books explain it

Natural Language Processing in Action, Second Edition

A forward index maps each document to the words or features it contains.

How it is used
Supports full-text search by organizing document contents before retrieval structures are created.
How deep it goes
Defines document-word listings and their inversion, but stops short of detailed implementation or storage design.
Examples
Uses documents containing “cat” and “cats,” word positions, and direct lookup versus document-by-document scanning.
What you can do after
Evaluate how document-first listings become inverted structures for faster keyword retrieval.

Read how Natural Language Processing in Action, Second Edition explains forward index →

AI-Powered Search

A forward index is a data structure that maps each document and field to the terms contained in that document.

How it is used
Supports faceting, aggregations, semantic traversal, and ranking over indexed search results.
How deep it goes
Defines document-to-term mapping and describes doc values and query-time uninversion, without detailing storage internals.
Examples
Uses three documents with job_title, desc, and skills fields to contrast forward and inverted mappings.
What you can do after
Understand how search engines generate facets and support relationship traversal from document-field term data.

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Related concepts

These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.