Question

Here’s what I’m doing:

1. Take a string
2. Check if HashSet contains the string
3. If it doesn’t, add the string to the HashSet (if it does, do something else)

This must work with a very large arrays of strings the fastest way possible

Is using HashSet the fastest way to check if string already has occured or is there something better for .net 4.5?

Answer 1

See the HashSet.Add

returns true if the element is added to the HashSet object; false if the element is already present.

HashSet<string> hs = new HashSet<string>();
bool b1 = hs.Add("xxx"); //returns true
bool b2 = hs.Add("xxx"); //returns false