Collections extensions

List

Random

// gets an random element of the list
var randomElement = myList.Random();
var randomElement = myList.Random(System.Random random); // using System.Random

// gets element of a list with a luck factor
var randomElement = myList.Random((i, element) => element.luck);
var randomElement = myList.Random((i, element) => element.luck, System.Random random); // using System.Random

IDictionary

RemoveAll

RemoveAll using a selector

myDictionary.RemoveAll(keyValue => keyValue.Value == null);

Contains

Contains using a selector

myDictionary.Contains(keyValue => ...);

TryGetValue

TryGetValue using a selector

KeyValuePair<int, int> v;
if (myDictionary.TryGetValue(keyValue => keyValue.Key > 10, out v)) {
    return v;
}

FirstOrNull

FirstOrNull using a selector. Returns a System.Nullable

var v = myDictionary.FirstOrNull(keyValue => keyValue.Key > 10, out v);
if (v.HasValue) {
    return v.Value.Value;
}