Subject: Re: hashtable w/o keys stored...
From: Erik Naggum <erik@naggum.no>
Date: 1999/01/18
Newsgroups: comp.lang.lisp
Message-ID: <3125682171162255@naggum.no>

* "Marc Battyani" <Marc_Battyani@csi.com>
| It's because to compute a hash value you have to process all the
| characters of your string.
: 
| All this depends on the statistical repartition of your keys.   You can
| imagine a data set with 100 characters keys on where the first 5 are
| usually enough to differentiate them.  In that case It's likely that
| hashtables will be slower.

  in all likelihood, a hashing function is able to take advantage of the
  same property of the input, and but then somewhat more for collisions.

  the real difference, as I see it, is that tries will be able to take
  advantage of _any_ smallest set of differences, so if you have a bunch of
  people names starting with "Smith", the trie will effectively just move
  past the first 5 and use the next 5 characters, instead.  a hash function
  would have to be excessively intelligent to adapt the same way.

#:Erik
-- 
  SIGTHTBABW: a signal sent from Unix to its programmers at random
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