[Casimiro Noteví]

Código Delphi [-]
program Project1;

{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  Spring,
  Spring.Collections;

type
  TProduct = class
  public
    Name: string;
    Category: string;
    Price: Double;
    InStock: Integer;
    
    constructor Create(const AName, ACategory: string; APrice: Double; AInStock: Integer);
  end;

constructor TProduct.Create(const AName, ACategory: string; APrice: Double; AInStock: Integer);
begin
  Name := AName;
  Category := ACategory;
  Price := APrice;
  InStock := AInStock;
end;

var
  Products: IList;
  Nombres: IEnumerable<string>;

begin
  try
    Products := TCollections.CreateObjectList(True);
    
    Products.AddRange([
      TProduct.Create('artilugio', 'cacharro', 192.43, 3),
      TProduct.Create('cacharro', 'electrónica', 13.65, 10),
      TProduct.Create('pongo', 'cacharro', 52.22, 0),
      TProduct.Create('cosa', 'electrónica', 11.33, 5),
      TProduct.Create('trasto', 'cacharro', 43.44, 1)
    ]);

    Writeln('Buscando nombres de electronica...');
    
    // Usando Map en lugar de Select
    Nombres := Products
      .Where(function(const p: TProduct): Boolean
        begin
          Result := p.Category = 'electrónica';
        end)
      .Map<string>(function(const p: TProduct): string
        begin
          Result := p.Name;
        end);

    for var s in Nombres do
      Writeln('Producto: ' + s);
      
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  
  Readln;
end.