Engineer's Toolbox

Hashing in Mathematica

Volume 2, Issue 4
Fall 1992

Hashing is a technique for mapping arbitrary expressions to some range of integers and is useful for efficient storage and retrieval of data. Although Mathematica provides efficient means of accessing the data associated with symbols, there are some situations in which it is helpful to hash to either an index into an array or to a symbol to which data can be attached using TagSet or UpSet. These hashing techniques are illustrated using two real-life problems. A package is presented that will hash an arbitrarily complex expression to a symbol.