hash-code-uniqueness - w3toppers.com

Probability of getting a duplicate value when calling GetHashCode() on strings

Large. (Sorry Jon!) The probability of getting a hash collision among short strings is extremely large. Given a set of only ten thousand distinct short strings drawn from common words, the probability of there being at least one collision in the set is approximately 1%. If you have eighty thousand strings, the probability of there … Read more

Why is ‘397’ used for ReSharper GetHashCode override?

Probably because 397 is a prime of sufficient size to cause the result variable to overflow and mix the bits of the hash somewhat, providing a better distribution of hash codes. There’s nothing particularly special about 397 that distinguishes it from other primes of the same magnitude.