---
id: "ddc"
kind: "datatype"
status: "draft"
is_pii: false
categories: ["publishing"]
langs: ["common"]
quality: 90
url: "https://registry.apicrafter.io/datatype/ddc"
---

# Dewey Decimal Classification (DDC) number (`ddc`)

> **Draft.** Draft records have not been reviewed yet and may be incomplete or wrong; do not treat them as authoritative for legal or compliance decisions.

Class number of the Dewey Decimal Classification, the library classification maintained by OCLC and used by public and school libraries and by national bibliographies in many countries. A number has three digits for the main class, division and section, such as 700 for the arts, and an optional decimal part for narrower subjects, such as 791.4. Numbers from the auxiliary tables are written with the table number and two hyphens, such as 2--4897 for Finland in Table 2 (geographic areas). The regexp is the Wikidata format of property P1036; it does not accept the letters and Cutter numbers of a full call number.

- Personal data (PII): no
- Categories: Publishing and print (publishing)
- Countries: global
- Languages: Common to most languages (common)
- Classification: categorical

## Detection

Regular expression (Python `re`):

```
^(?:\d{3}(?:\.\d+)?|[12456]--\d+|3[ABC]?--\d+)$
```

## Examples

- `700` — The arts
- `791.4` — Radio (Wikidata example)
- `2--4897` — Finland, Table 2 notation
- `79` (invalid example) — Fewer than three digits

## Mappings

- wikidata: `P1036`

## Translations

- ru: Индекс Десятичной классификации Дьюи (ДКД): Классификационный индекс библиотечной классификации Дьюи: три цифры класса и, при необходимости, десятичная часть.

## Sources

- wikipedia: <https://en.wikipedia.org/wiki/Dewey_Decimal_Classification>
- wikidata: <https://www.wikidata.org/wiki/Property:P1036>
- doc: <https://www.oclc.org/en/dewey.html>

## Quality

Score 90/100. Missing: detector coverage.

JSON: <https://registry.apicrafter.io/api/v1/datatypes/ddc.json> · Edit: <https://github.com/apicrafter/metacrafter-registry/edit/main/data/datatypes/any/publishing/ddc.yaml>