Fluent Random Picker is a nice, performant, fluent way to pick random values. Probabilities can be specified, values can be weighted.
$ dotnet add package FluentRandomPicker
Fluent Random Picker is a user-friendly, but also performant .NET library that simplifies random value selection / picking. It allows you to specify probabilities and weights for each value, making it easy to handle complex randomization tasks.
Fluent Random Picker targets .Net Standard 2.0 and is therefore compatible with the following target frameworks:
Install the nuget package (https://www.nuget.org/packages/FluentRandomPicker/)
Add the using directive:
using FluentRandomPicker;To get started, use the Out.Of() syntax as shown in the examples below:
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();
// 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();
// randomString is "hello" or "world", but the probability for "world" is 1.5 times as high.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 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(70)
.AndValue(10).WithPercentage(15)
.AndValue(100).WithPercentage(10)
.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], ..., [1000, 100], 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. Please see README-Advanced.md for more advanced topics like:
The namespace was changed to match coding conventions. Please replace:
using Fluent_Random_Picker;with
using FluentRandomPicker;Some method parameter identifiers do also have changed to match the coding conventions of Microsoft.