There are infinite ways to hash a string into a long. What have you tried? What problems are you having? Have you tried googling "vb.net " - Corbin 2012-04-04 04:51

yea, what? md5 hash would has a string into a byte () - user4951 2012-04-04 04:52

possible duplicate of How to ensure that a file has unique line in vb.net if the size of the file is very bigGreg Hewgill 2012-04-04 04:53

You can convert an array of bytes into a long. However, most hashing algorithms create a hash too large to fit in a single long. What is wrong with an array of bytes - Corbin 2012-04-04 04:53

Basically, I can tolerate that several different strings are hashed into the same long. The file is large, so I want to minimize memory usage as much as possible - user4951 2012-04-04 04:55

A long is 64 bits in VB.net, if I remember correctly. An md5 hash is 128 bits. That's not much of a difference in the big scheme of things. I'm sure there's some hashing algo out that that produces a hash <= 64 bits - Corbin 2012-04-04 04:57

Actually GetHashCode will convert that to integer, which is 32 bit. Good enough. I thought md5 is long string - user4951 2012-04-04 05:07

Okay, say I use md5, which is 128 bit. How to compare that the has is already around - user4951 2012-04-04 06:51

Ah I get it. Hmm.. gethashcode will give you an integer hash. While that's fine a normal long has would work too - user4951 2012-04-04 07:14