How to avoid duplicate value in list Using C# in unity

Question

I am newbie in unity and use C#, actually i am python developer i try to make a list which can holds only unique Values and if some duplicate value come it will not allow to enter in list

List<int> iList = new List<int>();
    iList.Add(2);
    iList.Add(3);
    iList.Add(5);
    iList.Add(7);

list =[2,3,5,7]

**in python we just do this to avoid duplicate in list **

if(iList.indexof(value)!=-1){
iList.append(value)
}

But what should we do in C# to achieve very similar results Thanks Your effort will be highly appreciated

Answer 1

C# List has similar method: if (!iList.Contains(value)) iList.Add(value);

Alternatively you can use a HashSet<int>. There you don't need to add any conditions:

var hasSet = new HashSet<int>(); 
hashSet.Add(1);
hashSet.Add(1);