Jump to navigation Jump to search This article is about a programming concept. This article needs bitcoin mining algorithm explained variance citations for verification. A hash function that maps names to integers from 0 to 15.
There is a collision between keys “John Smith” and “Sandra Dee”. A hash function is any function that can be used to map data of arbitrary size to data of a fixed size. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. Thus, the hash function only hints at the record’s location. Still, in a half-full table, a good hash function will typically narrow the search down to only one or two entries.
Hash functions are also used to build caches for large data sets stored in slow media. A cache is generally simpler than a hashed search table, since any collision can be resolved by discarding or writing back the older of the two colliding items. This is also used in file comparison. When storing records in a large unsorted file, one may use a hash function to map each record to an index into a table T, and to collect in each bucket T a list of the numbers of all records with the same hash value i. Once the table is complete, any two duplicate records will end up in the same bucket.