Question

I was going to create an In extension method on int, when I realized, if I use IEquatable I’d get the extension on all primitive types. This is my current implementation

public static bool In<T>(this T value, params T[] values) where T : IEquatable<T>
{
    return values.Contains(value);
}

It works just fine if(i.In(1,3,7)) for ints, but the where T: IEquatable<T> just looks wrong to me. Is this the correct way to define the generic method?

Answer 1

What you have looks right to me. You’re saying that the type must implement IEquatable<T> for its own type.

You could also extend it to say that the type you’re comparing against can be a different type that implements IEquatable<T> for the value:

public static bool In<T, U>(this T value, params U[] values) where U : IEquatable<T>
{
    bool result = false;
    foreach (U instance in values)
    {
        if (instance.Equals(value))
        {
            result = true;
            break;
        }
    }
    return result;
}