Re: hash function for large strings

It depends on what possible values of each character of the string you can
exclude. If they can be each of the possible 256 characters, there are
limited hashing possibilities; you can treat upper- and lowercase letters
the same, since VLOOKUP will do that anyway. But that doesn't save you a
lot. If there are just the alphabet and 0-9, you can exclude a lot more.
Then you can use a number base conversion function to realize the gain in
storage requirement. It may, however, be difficult to find one that uses all
256 possibilities. I have seen one (from Ron Rosenfeld) that uses 0-9 and
upper- and lowercase letters.

I find it difficult to believe that there isn't any logic behind the
population of your keys. Still that is the "key" to hashing.

Can you tell a bit more about the nature of your keys?

Kind regards,

Niek Otten

"jheby" <jheby@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
Excel vlookup function returns #VALUE when the lookup value exceeds 256
characters. I need a hash function to transform large strings into a
that does not exceed the 256 character limit. Are there any quick
to this problem?