Jump to content

Multimap

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 166.173.250.23 (talk) at 17:38, 15 September 2015 (Add content). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Ipv6 security no mapping

Examples

  • In a student enrollment system, where students may be enrolled in multiple classes simultaneously, there might be an association for each enrollment of a student in a course, where the key is the student ID and the value is the course ID. If a student is enrolled in three courses, there will be three associations containing the same key.
  • The index of a book may report any number of references for a given index term, and thus may be coded as a multimap from index terms to any number of reference locations.
  • Querystrings may have multiple values associated with a single field. This is commonly generated when a web form allows multiple check boxes or selections to be chosen in response to a single form element.

Language support

C++

C++'s Standard Template Library provides the multimap container for the sorted multimap using a self-balancing binary search tree,[1] and SGI's STL extension provides the hash_multimap container, which implements a multimap using a hash table.[2]

Dart

Quiver provides a Multimap for Dart.[3]

Java

Apache Commons Collections provides a MultiMap interface for Java.[4] It also provides a MultiValueMap implementing class that makes a MultiMap out of a Map object and a type of Collection.[5]

Google Guava provides an interface Multimap and implementations. [6]

OCaml

OCaml's standard library module Hashtbl implements a hash table where it's possible to store multiple values for a key.

Scala

The Scala programming language's API also provides Multimap and implementations[7]

See also

References

  1. ^ "multimap<Key, Data, Compare, Alloc>". Standard Template Library Programmer's Guide. Silicon Graphics International.
  2. ^ "hash_multimap<Key, HashFcn, EqualKey, Alloc>". Standard Template Library Programmer's Guide. Silicon Graphics International.
  3. ^ "Multimap". Quiver API docs.
  4. ^ "Interface MultiMap". Commons Collections 3.2.1 API, Apache Commons.
  5. ^ "Class MultiValueMap". Commons Collections 3.2.1 API, Apache Commons.
  6. ^ "Interface Multimap<K,V>". Guava Library 2.0.
  7. ^ "Scala.collection.mutable.MultiMap". Scala stable API.