Dart5.Set

Set

•set1.difference(set2):返回set1集合里有但set2里没有的元素集合

•set1.intersection(set2)：返回set1和set2的交集

•set1.union(set2)：返回set1和set2的并集

•set1.retainAll()：set1只保留某些元素(要保留的元素要在原set中存在）

set.dart

void main(){
  /// ---------------------------------Sets集合:Set--------------------------------
  print('-----------------------Sets------------------------');
  //6.  Set无重复列表
  var dynamicSet = Set();
  dynamicSet.add('aaaaa');
  dynamicSet.add('flutter');
  dynamicSet.add(1);
  dynamicSet.add(1);
  print('dynamicSet :${dynamicSet}'); // 输出 dynamicSet :{aaaaa, flutter, 1}
  //常用属性与list类似

  //常用方法 增删改查与list类似
  var set1 = {'aaaaa', 'flutter'};
  print('set1 :${set1}'); // 输出 set1 :{aaaaa, flutter}
  var set2 = {'aaaaa', 'damon', 'dart'};
  print('set2 :${set2}'); // 输出 set2 :{aaaaa, damon, dart}
  var difference12 = set1.difference(set2);
  var difference21 = set2.difference(set1);
  print('set1 difference set2 :${difference12}'); //返回set1集合里有但set2里没有的元素集合 输出 set1 difference set2 :{flutter}
  print('set2 difference set1 :${difference21}'); //返回set2集合里有但set1里没有的元素集合 输出 set2 difference set1 :{damon, dart}
  var intersection = set1.intersection(set2);
  print('set1 set2交集 :${intersection}'); //返回set1和set2的交集 输出  set1 set2交集 :{aaaaa}
  var union = set1.union(set2);
  print('set1 set2并集 :${union}'); //返回set1和set2的并集 输出  set1 set2并集 :{aaaaa, flutter, damon, dart}
  set2.retainAll(['aaaaa', 'flutter']); //只保留(要保留的元素要在原set中存在） 输出  set2只保留aaaaa flutter :{aaaaa}
  print('set2只保留aaaaa flutter :${set2}');
  print('-----------------------Sets------------------------');
}

输出：

D:\flutter\bin\cache\dart-sdk\bin\dart.exe --enable-asserts --enable-vm-service:13394 D:\Code\Flutter\FlutterHello\flutter_app\lib\set.dart
lib/set.dart: Warning: Interpreting this as package URI, 'package:flutterapp/set.dart'.
Observatory listening on http://127.0.0.1:13395/cK5Bl72_rsc=/

-----------------------Sets------------------------
dynamicSet :{aaaaa, flutter, 1}
set1 :{aaaaa, flutter}
set2 :{aaaaa, damon, dart}
set1 difference set2 :{flutter}
set2 difference set1 :{damon, dart}
set1 set2交集 :{aaaaa}
set1 set2并集 :{aaaaa, flutter, damon, dart}
set2只保留aaaaa flutter :{aaaaa}
-----------------------Sets------------------------

Process finished with exit code 0