NAME¶

new-hash - (hash)

PURPOSE¶

Create hash.

SYNTAX¶

new-hash <hash> \


    [ process-scope ] \


    [ hash-size <hash size> ] 

DESCRIPTION¶

new-hash creates new <hash>. A hash is a collection of key/value pairs, called "elements". A value of an element is obtained based on its key value.

SCOPE

Note that a hash is accessible to the current request only, unless "process-scope" clause is used, in which case all requests served by a process can use it (see do-once for a typical way to create a hash with a process scope).

If "process-scope" is used, then <hash> will keep its data across all requests in a given process. See write-hash for an example of a process-scoped hash.

SIZING A HASH

A hash can be of any size, as long as there is enough memory for it. The "hash-size" refers to the size of a hash table used to provide high-performance access to its elements based on a key.

<hash size> is the number of "buckets" used by the hash (it is 10 by default). All hash elements with the same hash code are stored in a linked list within the same bucket. Greater <hash size> generally means less elements per bucket and better performance. However, memory usage grows with a bigger hash table, so <hash size> should be balanced based on the program needs.

Golf uses high-performing FNV1_a hash algorithm. Each element in a bucket list is lightweight, containing pointers to a key, value and next element in the linked list.

<hash size> must be at least 256; if less, it will be set to 256.

EXAMPLES¶

Create a new hash with 5000 buckets:

new-hash h hash-size 5000

See read-hash for more examples.

SEE ALSO¶

Hash

get-hash new-hash purge-hash read-hash resize-hash write-hash See all documentation