using FluentRandomPicker;

Out.Of()...

var randomNumber = Out.Of().Value(5).AndValue(6).PickOne();
// randomNumber is 5 or 6 with equal probability.

var randomChar = Out.Of()
                  .Value('a').WithPercentage(70)
                  .AndValue('b').WithPercentage(30)
                  .PickOne();
// or
var randomChar = Out.Of().Values(new List<char> { 'a', 'b' })
                  .WithPercentages(70, 30)
                  .PickOne();
// or
var randomChar = Out.Of().Values(new List<char> { 'a', 'b' })
                  .WithPercentages(new List<int> { 70, 30 })
                  .PickOne();
// randomChar is 'a' with a probability of 70 % and 'b' with a probability of 30 %.

var randomString = Out.Of()
                  .Value("hello").WithWeight(2)
                  .AndValue("world").WithWeight(3)
                  .PickOne();
// or
var randomChar = Out.Of().Values(new HashSet<string> { "hello", "world" })
                  .WithWeights(2, 3)
                  .PickOne();
// or
var randomChar = Out.Of().Values(new HashSet<string> { "hello", "world" })
                  .WithWeights(new List<int> { 2, 3 })
                  .PickOne();
// randomString is "hello" or "world", but the probability for "world" is 1.5 times as high.

var randomInts = Out.Of()
                  .Value(1).WithPercentage(80)
                  .AndValue(10).WithPercentage(10)
                  .AndValue(100).WithPercentage(5)
                  .AndValue(1000).WithPercentage(5)
                  .Pick(5);
// randomInts can be [1, 1, 1, 1, 1] with a higher probability or [1, 1, 100, 10, 1]
// or even [1000, 1000, 1000, 1000, 1000] with a very small probability.

var randomInts = Out.Of()
                  .Values(new List<int> { 1, 10, 100, 1000 })
                  .WithPercentages(70, 15, 10, 5)
                  .PickDistinct(2);
// randomInts can be [1, 10], [1, 100], [1, 1000] ... but not [1, 1], [10, 10], ...

class Item {
    public int Rarity { get; set; }
    public string Name { get; set; }
}

var items = new Item[]
{
    new Item { Name = "Stone", Rarity = 5 }, // common
    new Item { Name = "Silver helmet", Rarity = 2 }, // uncommon
    new Item { Name = "Gold sword", Rarity = 1 }, // rare
};

var itemName = Out.Of()
                  .PrioritizedElements(items)
                  .WithValueSelector(x => x.Name)
                  .AndWeightSelector(x => x.Rarity)
                  .PickOne();

// itemName is "Stone" in 5/8 of the cases, "Silver helmet" in 2/8 of the cases and "Gold sword" in 1/8 of the cases.
// If no value selector is specified, the whole item object will be returned instead of only its name.

var randomChar = Out.Of()
                  .Value('a').WithPercentage(80)
                  .AndValue('b') // no percentage
                  .AndValue('c') // no percentage
                  .PickOne();
// The missing percentages to reach 100% are equally distributed on the values without specified percentages.
// Attention! The missing percentages to reach 100% must be divisible without remainder through the number of values without percentages.
// randomChar is 'a' with a probability of 80% or 'b' or 'c' with a probability of each 10%.

var randomString = Out.Of()
                  .Value("hello").WithWeight(4)
                  .AndValue("world") // no weight
                  .PickOne();
// The default weight is 1.
// randomString is "hello" with a probability of 80% (4 of 5) and "world" with a probability of 20% (1 of 5).

var operation = Out.Of<Func<long, long>>()
                .Value(i => i + 2)
                .AndValue(i => i * 2)
                .AndValue(i => (long)Math.Pow(i, 2))
                .AndValue(i => (long)Math.Pow(i, i))
                .PickOne();

var result = operation(10);
// result equals 10 + 2 or 10 * 2 or 10^2 or 10^10. 

var seed = 1234567;

var value1 = Out.Of(seed).Values(new[] { 1, 2, 3, 4 }).PickOne();
var value2 = Out.Of(seed).Values(new[] { 1, 2, 3, 4 }).PickOne();
// value1 and value2 are always equal.

var secureRng = new FluentRandomPicker.Random.SecureRandomNumberGenerator();
var value = Out.Of(secureRng).Values(new[] { 1, 2, 3, 4 }).PickOne();

public class MyOwnRandomNumberGenerator : IRandomNumberGenerator
{
    public double NextDouble()
    {
        // ...
    }

    public int NextInt()
    {
        // ...
    }

    public int NextInt(int n)
    {
        // ...
    }

    public int NextInt(int min, int max)
    {
        // ...
    }
}

var myRng = new MyOwnRandomNumberGenerator();
var value = Out.Of(myRng).Values(new[] { 1, 2, 3, 4 }).PickOne();
// value gets picked via a specified random number generator.

using Fluent_Random_Picker;

using FluentRandomPicker;

Out.Of().Values(1, 2, 3)...

Out.Of().Value(1).AndValue(2).AndValue(3)...

Out.Of().Values(new List<int>{ 1, 2, 3 })...