Best way to find out if IEnumerable<> has unique values

Question

I have a lot of code in which I do something like this

bool GetIsUnique(IEnumerable values)
{
    return values.Count() == values.Distinct().Count;
}
         


        

Answer 1

I would make this a nice extension method

public static bool IsUnique(this IEnumerable list)
{
    var hs = new HashSet();
    return list.All(hs.Add);  
}

Checks that all items can be added to a HashSet.