在此处使用map .教程。
例如：

class City {
  const City(this.id, this.name);

  final int id;
  final String name;
}

List<City> cities = [
  City(0, 'A'),
  City(1, 'B'),
  City(2, 'C'),
];

final List<String> cityNames = cities.map((city) => city.name).toList();

void main() {
  print(cityNames);
}

虽然很简单也很麻烦

var cityNames = cities.map((c) => c.name).toList().join(',');

List<String> names=[];

for (City city in cities){
names.add(city.name);
 }

用这个

List<String> cityNameList = cities.map((city) => city.name).toList();

• 您也可以通过下面的解释 *
  自定义数据类

class City {
    String id;
    String name;
    String parent_id;
    double lat;
    double lng;
    String local;
}

基于City类的任何成员将List<City>Map到List<String>

List<City> cities= getListOfCities();
// city.name, city.local...any field as you wish
List<String> cityNameList = cities.map((city) => city.name).toList();
print(cityNameList);