A problem you might run to in the course of your application development is that given a array of items, sample a number of elements randomly.

There are two ways we can attempt this:

Random Sorting, Take N Elements

The first (and more inefficient way) is to sort the array randomly, and then pick the desired number of elements from the head of the array.

var numbers = Enumerable.Range(1, 25).ToArray();

var shuffled = numbers.OrderBy(n => Random.Shared.Next())
  .Take(10)
  .ToArray();

foreach (var number in shuffled)
{
  Console.Write($"{number} ");
}

This code will return 10 elements.

2 10 6 18 14 17 22 16 4 19

The drawback of this technique is that it sorts the entire array before sampling. Which can be inefficient if the array is large but you just want to sample a few items.

Random.GetItems Method

A much better way is to make use of the Random.GetItems method that achieves precisely this.

var sampled = Random.Shared.GetItems(numbers, 10);

foreach (var number in sampled)
{
  Console.Write($"{number} ");
}

This is much cleaner and terser, and avoids the overhead of sorting the entire array first before selecting the required elements.

This code will return 10 elements.

24 3 22 9 3 10 2 18 15 21

Random.GetItems also works with Spans.

TLDR

The Random.GetItems method can be used to randomly sample elements of an array.

The code is in my GitHub.

Happy hacking!