Whats the most concise way to pick a random element by weight in c#?

Question

Lets assume:

List which element is:

public class Element(){
   int Weight {get;set;}
}

What I want to a

Answer 1

If you want a generic version (useful for using with a (singleton) randomize helper, consider whether you need a constant seed or not)

usage:

randomizer.GetRandomItem(items, x => x.Weight)

code:

public T GetRandomItem(IEnumerable itemsEnumerable, Func weightKey)
{
    var items = itemsEnumerable.ToList();

    var totalWeight = items.Sum(x => weightKey(x));
    var randomWeightedIndex = _random.Next(totalWeight);
    var itemWeightedIndex = 0;
    foreach(var item in items)
    {
        itemWeightedIndex += weightKey(item);
        if(randomWeightedIndex < itemWeightedIndex)
            return item;
    }
    throw new ArgumentException("Collection count and weights must be greater than 0");
}