Round #886

Use Random.Shared to pick a random element from a List<T> in a generic Pick<T>(List<T>) extension method.

### Random Element Picker Extension Method Below is a simple implementation of a generic extension method `Pick` that uses `Random.Shared` to select a random element from a `List<T>`. ```csharp using System; using System.Collections.Generic; public static class ListExtensions { /// <summary> /// Picks a random element from the list. /// </summary> /// <typeparam name="T">Type of elements in the list.</typeparam> /// <param name="list">The list to pick an element from.</param> /// <returns>A random element from the list, or default(T) if the list is empty.</returns> public static T Pick<T>(this List<T> list) { if (list == null) { throw new ArgumentNullException(nameof(list)); } if (list.Count == 0) { return default(T); } int index = Random.Shared.Next(list.Count); return list[index]; } } ``` ### Example Usage Here's how you can use the `Pick` extension method: ```csharp public class Program { public static void Main() { List<string> colors = new List<string> { "Red", "Green", "Blue", "Yellow" }; string randomColor = colors.Pick(); Console.WriteLine($"Random color: {randomColor}"); List<int> numbers = new List<int> { 1, 2, 3, 4, 5 }; int randomNumber = numbers.Pick(); Console.WriteLine($"Random number: {randomNumber}"); List<string> emptyList = new List<string>(); string randomElementFromEmptyList = emptyList.Pick(); Console.WriteLine($"Random element from empty list: {randomElementFromEmptyList}"); } } ``` This code defines a `Pick` extension method that can be used on any `List<T>`. It uses `Random.Shared` to generate a random index into the list and returns the element at that index. If the list is empty, it returns the default value for the type `T`. The example usage demonstrates how to use this method with lists of different types.

```csharp using System; using System.Collections.Generic; public static class ListExtensions { public static T Pick<T>(this List<T> list) { if (list == null) { throw new ArgumentNullException(nameof(list)); } if (list.Count == 0) { throw new InvalidOperationException("List is empty"); } return list[Random.Shared.Next(list.Count)]; } } ``` This extension method uses `Random.Shared` to generate a random index into the list, and then returns the element at that index. It includes error checking to handle null lists and empty lists.