# Re: hash function for large strings

*From*: "Niek Otten" <nicolaus@xxxxxxxxx>*Date*: Tue, 7 Mar 2006 18:54:30 +0100

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

news:FB83AD4A-0184-4717-A8E7-8EC893FC86AE@xxxxxxxxxxxxxxxx

Excel vlookup function returns #VALUE when the lookup value exceeds 256

characters. I need a hash function to transform large strings into a

value

that does not exceed the 256 character limit. Are there any quick

solutions

to this problem?

.

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