Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Name–value pair
Résumé
A name–value pair, also called an attribute–value pair, key–value pair, or field–value pair, is a fundamental data representation in computing systems and applications. Designers often desire an open-ended data structure that allows for future extension without modifying existing code or data. In such situations, all or part of the data model may be expressed as a collection of 2-tuples in the form with each element being an attribute–value pair. Depending on the particular application and the implementation chosen by programmers, attribute names may or may not be unique.
Some of the applications where information is represented as name–value pairs are:
E-mail, in RFC 2822 headers
Query strings, in URLs
Optional elements in network protocols, such as IP, where they often appear as TLV (type–length–value) triples
Bibliographic information, as in BibTeX and Dublin Core metadata
Element attributes in SGML, HTML and XML
Some kinds of database systems – namely a key–value database
OpenStreetMap map data
Windows registry entries
Environment variables
Some computer languages implement name–value pairs, or more frequently colllections of attribute–value pairs, as standard language features. Most of these implement the general model of an associative array: an unordered list of unique attributes with associated values. As a result, they are not fully general; they cannot be used, for example, to implement electronic mail headers (which are ordered and non-unique).
In some applications, an name–value pair has a value that contains a nested collection of attribute–value pairs. Some data serialization formats such as JSON support arbitrarily deep nesting.
Other data representations are restricted to one level of nesting, such as 's section/name/value.
Source officielle
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.