map.dart

// En otros lenguajes se conoce como diccionario

main(List<String> args) {
  Map <String, String> mi = { 'one':'first', 'two': 'second'};
  print(mi['two']); /*second*/
  
  mi['tree'] = 'third';
  print(mi); //{one: first, two: second, tree: third}
  
  print(mi.runtimeType); /*JsLinkedHashMap<String, String>*/
  
  
  Map<String, String> m = new Map();

  m.addAll({"one": "first number"});
  print(m); /* {one: first number} */

  m.addAll({"two": "second"});
  print(m); /* {one: first number, two: second} */
  
  /* -------------------------------------------------------------------------- */
  /*                   Agregar un valor si no existe una llave                  */
  /* -------------------------------------------------------------------------- */
  
  Map<int, int> mne = {1:10, 2:20, 3:30};
  mne.putIfAbsent(5, (){
    return 50;
  });
  print(mne); /*{1: 10, 2: 20, 3: 30, 5: 50} si es q existe no hace nada*/

  /* -------------------------------------------------------------------------- */
  /*                                  recorrer                                  */
  /* -------------------------------------------------------------------------- */
  m.forEach((key, value) {
    print("$key $value");
  });

  /* -------------------------------------------------------------------------- */
  /*                                 actualizar                                 */
  /* -------------------------------------------------------------------------- */
  m.update("one", (value) => "first");
  print(m); /* {one: first, two: second} */

  /* -------------------------------------------------------------------------- */
  /*                                  eliminar                                  */
  /* -------------------------------------------------------------------------- */
  m.remove("two");
  print(m); /* {one: first} */

  m.addAll({"tree": "thirth"});
  print(m); /* {one: first, tree: thirth} */
  m.removeWhere((key, value) => key == "tree");
  print(m); /* {one: first} */
  
  /* -------------------------------------------------------------------------- */
  /*                             Obtener keys y values                          */
  /* -------------------------------------------------------------------------- */
  Map<String, String> mkv = {'a': 'A', 'b':'B'};
  
  List<String> k = mkv.keys.toList();
  print('claves $k');/*claves [a, b]*/
  
  List<String> v = mkv.values.toList();
  print('valores $v');/*valores [A, B]*/
  
}