C#

Collections, LINQ and asynchronous code in modern C#.

Tooling

dotnet new console -n DemoCreate a console project

dotnet buildBuild the project

dotnet runRun the project

dotnet testRun tests in a test project or solution

var names = new List<string> { "Ada", "Lin" };Create a mutable list

names.Add("Sam");Append an element

names.Where(n => n.StartsWith("A")).ToList();Materialize a filtered sequence

names.Select(n => n.ToUpperInvariant());Produce a lazy projection

string? nickname = null;Permit null with nullable reference types enabled

var length = nickname?.Length ?? 0;Safely access a nullable string

var text = await File.ReadAllTextAsync(path);Read without blocking the calling thread

using var stream = File.OpenRead(path);Dispose a resource at the end of its scope