Dart之集合详解(List、Set、Map)

main() {
//  定义一个int类型数组
  List list1 = <int>[1, 2];
  print(list1); //[1, 2]
//  length长度
  print(list1.length); //2
// reversed翻转
  print(list1.reversed.toList()); //[2, 1]
// isEmpty 是否为空
  print(list1.isEmpty); //false
//isNotEmpty 是否不为空
  print(list1.isNotEmpty); //true
//add添加
  list1.add(3);
  print(list1); //[1, 2, 3]
//addAll 添加一个数据
  list1.addAll(<int>[4, 5]);
  print(list1); //[1, 2, 3, 4, 5]
//indexOf 查找 传入具体指 找到返回索引，否则返回-1
  print(list1.indexOf(1)); //0
  print(list1.indexOf(90)); //-1
//remove 删除具体值
  list1.remove(4); //[1, 2, 3, 5]
  print(list1);
//removeAt 删除 传入索引
  list1.removeAt(0);
  print(list1); //[2, 3, 5]
//fillRange 修改
  list1.fillRange(1, 2, 89); //[2, 89, 5]
  print(list1);
  //insert 插入值
  list1.insert(2,
      99); //[2, 89, 99, 5] 如果插入位置大于现在拥有的下标-》Invalid value: Not in inclusive range 0..3: 7
  print(list1);
  //insertAll 插入数组
  list1.insertAll(2, <int>[33, 44]);
  print(list1); //[2, 89, 33, 44, 99, 5]
  //toList 其它类型转换为List
  var str = list1.toString();
  print(str); //[2, 89, 33, 44, 99, 5]
  print(str.length); //22
  //join() List转换为字符串
  print(list1.join(":")); //2:89:33:44:99:5
  //split()字符串转换为list
  print("1,2,3".split(",") is List); //true
  //forEach
list1.forEach((element) {print(element);});//2  89  33  44  99  5
 
  //map 遍历每个元素，返回准换后的结果
  list1=list1.map((e) => e*2).toList();
  print(list1); //[4, 178, 66, 88, 198, 10]
  //where 过滤元素，保留满足条件的元素
  list1=list1.where((element) => element>87).toList();
  print(list1);//[178, 88, 198]
  //any 判断集合中是否有一个元素满足条件 element>188
  var condition_1= list1.any((element) => element>188);
  print(condition_1); //true
  //every 判断集合中是否有所有元素满足条件 element>188
  var condition_2= list1.every((element) => element>188);
  print(condition_2); //false
 
}

main() {
//  键-》值
  Map person = {"name": "zhangsan", 'age': 20};
//  获取长度
  print(person.length); //2
//  判断是否为空
  print(person.isNotEmpty); //true
//  获取运行是类型
  print(person.runtimeType); //_InternalLinkedHashMap<dynamic, dynamic>
//  获取hashCode
  print(person.hashCode); //1018109981
//  获取所有键
  print(person.keys.toList()); //[name, age]
//  获取所有值
  print(person.values.toList()); //[zhangsan, 20]
//添加键值对
  person.addAll({"work": "coding"});
  print(person); //{name: zhangsan, age: 20, work: coding}
//  产出一个键
  person.remove('age');
  print(person); //{name: zhangsan, work: coding}
//  判断是否包含值
  print(person.containsValue("coding")); //true
//  判断是否包含键
  print(person.containsKey("work")); //true
}

main(){
  var mySet=new Set();
  mySet.add(1);
  mySet.add(2);
  mySet.add(1);
  print(mySet);//{1, 2}
  print(mySet.toList());//[1, 2]
 
}

main() {
  List myList = ["a", "b", "c"];
//  for in
  for (var value in myList) {
    print(value);
  }
//  for
  for (int i = 0; i < myList.length; i++) {
    print(myList[i]);
  }
//  forEach
  myList.forEach((element) {
    print(element);
  });
  myList.forEach((element) => print(element));
 
}