array

//=========================
//Use toSet and then toList

var ids = [1, 4, 4, 4, 5, 6, 6];
var distinctIds = ids.toSet().toList(); //[1, 4, 5, 6]

//=========================
isEven(x) => x % 2 == 0;

main() {
  var list = [4,1,2];
  var evens = list.filter(isEven);
  printList(evens);
}

//=========================
var stuff = {"hello": "world", 'Dart': 'Is Cool'};
  stuff.putIfAbsent('foo', () {
    // calculate something awesome
    return 'bar';
  });
  print( stuff['foo'] ); // bar
  
 //=========================