Fluent Random Picker
Fluent Random Picker is a nice, performant fluent way to pick random values. Probabilities can be specified, values can be weighted.
Compatibility
✔️ .Net 5✔️ .Net Standard 2.0✔️ .Net Core 2.0✔️ .Net Framework 4.8✔️ .Net Framework 4.7.2❌ .Net Framework 4.6.X
Getting started
Install the nuget package (https://www.nuget.org/packages/FluentRandomPicker/)
Add the using directive:
using Fluent_Random_Picker;
Begin with Out.Of() (see the examples).
Out.Of()...
Examples
The easiest example
var randomNumber = Out.Of().Value(5).AndValue(6).PickOne();
// randomNumber is 5 or 6 with equal probability.
Specifying percentages
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 %.
Specifying weights
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.
Picking multiple values
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.
Picking distinct values
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], ...
Specifying the returned type explicitly
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.
Advanced
Specifying a seed
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 und value2 are always equal.
Using a different random number generator
The default random number generator is System.Random
public class MyOwnRandomNumberGenerator : IRandomNumberGenerator
{
public double NextDouble()
{
// ...
}
public int NextInt()
{
// ...
}
public int NextInt(int pN)
{
// ...
}
public int NextInt(int pMin, int pMax)
{
// ...
}
}
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.
Migration to version 2
The params array is not supported anymore for the Values method. Please replace
Out.Of().Values(1, 2, 3)...
with
Out.Of().Value(1).AndValue(2).AndValue(3)...
or
Out.Of().Values(new List<int>{ 1, 2, 3 })...
Reason: https://github.com/ndsvw/Fluent-Random-Picker/commit/da9af06bda215d0983e428072febed8f33577041