Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Pattern matching examples

object[] items = { 42, "hello", 3.14, true, null!, new List<int> { 1, 2 } };

foreach (var item in items)
{
    string result = item switch
    {
        int n when n > 0        => $"Positive int: {n}",
        int n                   => $"Non-positive int: {n}",
        string { Length: > 3 } s => $"Long string: {s}",
        string s                => $"Short string: {s}",
        double d                => $"Double: {d:F2}",
        bool b                  => $"Bool: {b}",
        null                    => "null value",
        _                       => $"Other: {item.GetType().Name}"
    };
    Console.WriteLine(result);
}

// Property pattern
record Person(string Name, int Age, string Country);
var alice = new Person("Alice", 30, "UK");

string category = alice switch
{
    { Age: < 18 }                           => "Minor",
    { Country: "UK", Age: >= 18 }           => "UK Adult",
    { Age: >= 65 }                          => "Senior",
    _                                        => "Adult"
};
Console.WriteLine(category); // "UK Adult"

// List pattern (C# 11)
int[] nums = { 1, 2, 3, 4, 5 };
bool matched = nums is [1, 2, .. var rest] && rest.Length > 0;
Console.WriteLine(matched); // True