null

• Explicit check

  if (x is null) { } // x == null

  if (x is not null) { } // x != null

• Conditional access (elvis operator)

  // `null` if `x` is not present
  x?.y;
  x?[y];

• Null coallescing

  var x = y ?? 2; // 2 if y is null

Cast

• Explicit check

  public record Person(string Name);

  if (x is Person) { } // `is` returns boolean

  if (x is Person y) {
      var z = y.Name;
  }

• Convert

  (int)x; // throws when cannot convert

  x as int; // returns null when cannot convert

Collections

• Empty array

  IList<int> x = new Array.Empty<int>();
  x.Add(); // throws!

• Anonymous type

  var x = new {
      Name = "John"
      Age = 21
  };

• List initializer

  var x = new List<int> { 1, 2, 3 };

  var x = new []{ 1, 2, 3 }; // int[]

  IList<int> x = new []{ 1, 2, 3 };
  x.Add(); // throws!

• Dictionary initializer

  var x = new Dictionary<string, int> {
      { "one", 1 }
      { "two", 2 }
  };

  var x = new Dictionary<string, int> {
      ["one"] = 1
      ["two"] = 2
  };

• Collections in object (dont know the name of this)

  public record Box {
      public IList<int> Toys { get; init; }
  }
  
  new Box {
      Toys = { "gameboy", "twister" }
  };

  public record Box {
      public IDictionary<string, int> Weather { get; init; }
  }
  
  new Box {
      Weather = {
          ["Adelaide"] = 40,
          ["Melbourne"] = 24
      }
  };