Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
http://msdn.microsoft.com/en-us/library/system.object.gethashcode(VS.80).aspx says:
For the best performance, a hash function must generate a random distribution for all input.
Does it have any effect in performance or it’s ok to use a function (like return this.Id) that doesn’t give a ‘random distribution’ but it doesn’t cause more collisions?
Using this.Id is generally okay. The underpinning is that you don’t want too many collisions which would end up in the same bucket. The bucket number is generally obtained by taking the hash code and considering it ‘mod x’ where x is the number of buckets in your hash table, and is usually prime (or a probable prime).
If you’re just using increasing IDs (1, 2, 3, 4…) that’s going to end up being pretty random as far as the bucket distribution is concerned. It’s only if your ID followed a pattern which might well give the same bucket number for lots of entries that you’d need to worry.