hash table

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hash table

hash table

A lookup table that is designed to efficiently store non-contiguous keys (account numbers, part numbers, etc.) that may have wide gaps in their alphabetic or numeric sequences.

Hash tables are created with an algorithm that stores the keys into hash buckets, which contain key-value pairs. Since different keys may hash to the same bucket, the goal of hash table design is to spread out the key-value pairs evenly with each bucket containing as few key-value pairs as possible. When an item is looked up, its key is hashed to find the appropriate bucket, and the bucket is then compared to find the right key-value pair. See key-value pair, cryptographic hash function and DHT.


A Hash Table
When an item is looked up, its key is hashed into a bucket value, and the bucket is compared to find the key.
References in periodicals archive ?
For a hash-table index, the average time to search for a cell is O(1) while worst-case time is O(N) where N is the number of cells in the list.
One implementation uses a hash-table based index while the other does not have a location index.
Although the hash-table index performs slightly better than the binary tree and red-black index, the difference among them is relatively small.