Collections

Sets

Unique Members

A set literal <T>{...} stores unique values. Adding a duplicate is a no-op.

Program

Play the program to add a duplicate and a new color, then read the length.

sets.dart 
void main() {
  var colors = <String>{'red', 'green'};
  colors.add('red');
  colors.add('blue');
  print(colors.length);
}
set literal `<String>{...}` declares an empty-or-seeded set.
uniqueness Adding an existing element does not grow the set.
length `length` reports the number of unique entries.