

Associative array  Wikipedia, the free encyclopedia 
  An associative array (also map, hash, dictionary, finite map, lookup table, and in queryprocessing an index or index file) is an abstract data type composed of a collection of keys and a collection of values, where each key is associated with one value. 
  Associative arrays are very closely related to the mathematical concept of a function with a finite domain. 
  Associative arrays can be implemented in any programming language, and one or more implementations of them is typically found either built into the language or the standard library distributed with it (C is a notable exception, as neither the language nor the standard library directly provide one). 
 en.wikipedia.org /wiki/Associative_array (3167 words) 
