C# Randomly choose items from a list

In C#, you can randomly slect items from a list using Random.GetItems, a method introduced in .NET 8.

public T[] GetItems<T>(T[] choices, int length)
Code language: C# (cs)

The method takes in two parameters:

• choices – the list of items to choose from / the list of possibilities.
• length – how many items to pick.

There are two important things to note about this method:

• the resulting list can contain duplicates, it is not a list of unique picks.
• this opens up the length parameter to be larger than the length of the list of choices.

With all this being said, let’s take a few examples. Let’s assume the following array of choices:

string[] fruits =
[
    "apple",
    "banana",
    "orange",
    "kiwi"
];
Code language: C# (cs)

For selecting 2 random fruits from that list, we simply call:

var chosen = Random.Shared.GetItems(fruits, 2);
Code language: C# (cs)

Now, as I’ve said before, the two chosen fruits are not necessarily unique. You could end up for example with [ "kiwi", "kiwi" ] as your chosen array. You can test this out easily with a d-while:

string[] chosen = null;

do
    chosen = Random.Shared.GetItems(fruits, 2);
while (chosen[0] != chosen[1]);

// At this point, you will have the same fruit twice
Code language: C# (cs)

And this opens the method up for selecting more items than you actually have in the list. In our example we have only 4 fruits to choose from, but we can ask GetItems to choose 10 fruits for us, and it will happily do it.

var chosen = Random.Shared.GetItems(fruits, 10);
// [ "kiwi", "banana", "kiwi", "orange", "apple", "orange", "apple", "orange", "kiwi", "apple" ]
Code language: C# (cs)