Question

I have a variable whose value is populated at runtime. I want to check whether that value is between two same datatype values (say lowest and highest) or not using an Extension Method.

I want to check like

int a = 2; //here static but is can be changed at runtime

if(a.Between(0,8))
   DoSomething();
else
   DoNothing();

If a is 0 or 8 or any value between them, it should return true.

If a is (-1 or less) or (9 or greater) then it should return false

i want to create an extension method like

public static bool Between<T1>(this T1 val1, T1 lowest, T1 highest) where ????
{
    What code to write here???? 
}

Answer 1

You can do it like this:

public static bool Between<T>(this T actual, T lower, T upper) where T : IComparable<T>
{
    return actual.CompareTo(lower) >= 0 && actual.CompareTo(upper) <= 0;
}

Reference here

Or if you want to do it on a collection you can do this:

public static IEnumerable<TSource> Between<TSource, TResult>
(
    this IEnumerable<TSource> source, Func<TSource, TResult> selector,
    TResult lowest, TResult highest
)
    where TResult : IComparable<TResult>
{
    return source.OrderBy(selector).
        SkipWhile(s => selector.Invoke(s).CompareTo(lowest) < 0).
        TakeWhile(s => selector.Invoke(s).CompareTo(highest) <= 0 );
}

Reference here

Usage:

var tenTo40 = list.Between(s => s, 10, 40);