Lists, sets and maps in Dart

The three core collections, each with its own literal.

void main() {
  // Lists index, sets deduplicate, maps pair keys with values.
  final route = ['gate', 'boardwalk', 'tower'];
  print(route[1]);

  final ringed = ['wren', 'robin', 'wren'].toSet();
  print('${ringed.length} distinct ringed species');

  final perchCounts = {'oak': 4, 'fence': 9};
  perchCounts['reeds'] = 2;
  print(perchCounts['fence']);
  print(perchCounts.containsKey('willow'));
}

How it works

1. Lists index with brackets; route[1] is the second stop.
2. toSet() deduplicates — three entries collapse to two.
3. Map literals pair keys to values; indexing a missing key gives null.

Keywords and builtins used here

• final
• void

The run, in numbers

Lines

13

Characters to type

384

Tokens

113

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 97 seconds.

Type this snippet

Step 1 of 3 in Collections, step 10 of 27 in Language basics.

← Previous Next →