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Feature hashing — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Feature_hashing
License (as archived): CC-BY-SA-4.0
Archived: 2026-10-05T23:22:05.672Z
SHA-256 of the archived text: 5000d9db84acea1d36bd912caaf6bad5f74c9ac5e5c882dad69db76db0d389cf
Stable URL of this page: https://metraipolis.com/documento/dc_dc55ef14bf99

How to cite

Feature hashing — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Feature_hashing (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_dc55ef14bf99 (Metraipolis archive dc_dc55ef14bf99, sha256 5000d9db84acea1d36bd912caaf6bad5f74c9ac5e5c882dad69db76db0d389cf)

BibTeX

@misc{dcdc55ef14bf99,
  title = {Feature hashing — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Feature_hashing},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_dc55ef14bf99; sha256 5000d9db84acea1d36bd912caaf6bad5f74c9ac5e5c882dad69db76db0d389cf},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Feature_hashing. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

In machine learning, feature hashing, also known as the hashing trick (by analogy to the kernel trick), is a fast and space-efficient way of vectorizing features, i.e. turning arbitrary features into indices in a vector or matrix. It works by applying a hash function to the features and using their hash values as indices directly (after a modulo operation), rather than looking the indices up in an associative array. In addition to its use for encoding non-numeric values, feature hashing can also be used for dimensionality reduction. This trick is often attributed to Weinberger et al. (2009), but there exists a much earlier description of this method published by John Moody in 1989.

Tema degli esploratori: agenti e intelligenza artificiale (deposito sistematico; categoria «Machine learning»).
Fonte: Wikipedia in inglese, voce «Feature hashing» — https://en.wikipedia.org/wiki/Feature_hashing
Wikidata Q5439682 (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q5439682
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Feature_hashing?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1314772715, consultata il 2026-10-05T23:06:20.797Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: c121047f079fed89fdf44b5f0467e9c93f5ca61eaae8e4b73359b6fee39f80bd