Params Collections in C# 13

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What Are Param Collections?

The params keyword in C# allows a method to accept a variable number of arguments, which must be a single-dimensional array. This parameter must be the last in the method signature, and only one params parameter is allowed per method.

How Is It Used?

Example of a method to calculate the sum of integers:

List<int> numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int results = CalculateSum(numbers.ToArray());

Console.WriteLine(results);

int CalculateSum(params int[] numbers)
{
    return numbers.Sum();

}

Limitations and Performance Considerations

Using params involves creating an array, which can affect performance, especially in loops or performance-critical code. Additionally, only one params parameter is allowed per method, and it must be the last parameter.

Changes in C# 13

C# 13 enhances the params keyword with:

• Support for Multi-Dimensional Arrays: Simplifies method calls and improves readability.
• Improved Type Inference: Better integration with generic methods and complex types.
• Performance Optimizations: Reduced overhead and improved performance for high-frequency method calls.

Examples

Enhanced CalculateSum method in C# 13:

List<int> numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int results = CalculateSum(numbers);

Console.WriteLine(results);

int CalculateSum(params List<int> numbers)
{
    return numbers.Sum();

}

Benchmarking the Performance

To evaluate the performance enhancements, we can set up a benchmark using BenchmarkDotNet:

using BenchmarkDotNet.Attributes;
using System;
using System.Collections.Generic;
using System.Linq;

[MemoryDiagnoser]
public class ParamsBenchmark
{
    private List<int> numbers;

    [GlobalSetup]
    public void Setup()
    {
        numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    }

    [Benchmark]
    public int CalculateSumWithList()
    {
        return CalculateSum(numbers);
    }

    [Benchmark]
    public int CalculateSumWithArray()
    {
        return CalculateSum(numbers.ToArray());
    }

    public int CalculateSum(params List<int> numbers)
    {
        return numbers.Sum();
    }

    public int CalculateSum(params int[] numbers)
    {
        return numbers.Sum();
    }
}

Output:

The benchmark results indicate that the new enhanced params implementation in C# 13 offers better performance with no additional memory overhead.

Conclusion

The enhancements in C# 13 make params collections more powerful and efficient, catering to more complex use cases and improving overall performance.