List

In Dart, arrays are List objects, so most people just call them lists.

var list = [1, 2, 3];

• Perhaps the most common collection in nearly every programming language is the array, or ordered group of objects.
• Lists use zero-based indexing, where 0 is the index of the first element and list.length - 1 is the index of the last element.

  var list = [1, 2, 3]; 
  assert(list.length == 3); 
  assert(list[1] == 2); 
  list[1] = 1; 
  assert(list[1] == 1);

• To create a list that’s a compile-time constant, add const before the list literal.

  var constantList = const [1, 2, 3]; 
  // constantList[1] = 1; // Uncommenting this causes an error

• You can use the spread operator (...) to insert all the elements of a list into another list.

  var list = [1, 2, 3];
  var list2 = [0, ...list];
  assert(list2.length == 4);

• If the expression to the right of the spread operator might be null, you can avoid exceptions by using a null-aware spread operator (...?).

  var list; 
  var list2 = [0, ...?list]; 
  assert(list2.length == 1);

• You can use collection if to create a list with three or four items in it.

  var nav = [ 'Home', 'Furniture', 'Plants', if (promoActive) 'Outlet' ];

• Using collection for to manipulate the items of a list before adding them to another list.

  var listOfInts = [1, 2, 3]; 
  var listOfStrings = [ '#0', for (var i in listOfInts) '#$i' ]; 
  assert(listOfStrings[1] == '#1');