A good hashing algorithm works a little like you're considering implementing by hand. Perl's hashing system uses "buckets". There may be a few or many items in each bucket. And each bucket itself is found quickly by the hashing algorithm. The result is a very efficient method where the correct bucket is quickly found, and then its contents are scanned for the particular item needed (this is a rough approximation of reality). Anyway, in the end, you get approximately O(1) lookups, which means constant time regardless of number of items in the lookup list.

The moral of this story is to use a hash to hold your 5000 strings. If they won't fit in memory that way, it's time to use a database solution and query for the needed string. But for maximum efficiency, just use the hash.


Dave

In reply to Re: comparing a string with lots of other strings by davido
in thread comparing a string with lots of other strings by matthewsnape

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