main.dart

const List<Map<String,dynamic>>rawData=[
  {
  "cityId": "01",
  "provinceName": "اردبيل",
  "cityName": "اردبيل",
  "provinceId": "24"
},
{
  "cityId": "11",
  "provinceName": "اردبيل",
  "cityName": "اصلاندوز",
  "provinceId": "24"
},
  {
  "cityId": "02",
  "provinceName": "اردبيل",
  "cityName": "بيله سوار",
  "provinceId": "24"
},
  {
  "cityId": "03",
  "provinceName": "اصفهان",
  "cityName": "خميني شهر",
  "provinceId": "10"
},
{
  "cityId": "04",
  "provinceName": "اصفهان",
  "cityName": "خوانسار",
  "provinceId": "10"
},
{
  "cityId": "23",
  "provinceName": "اصفهان",
  "cityName": "خور و بيابانک",
  "provinceId": "10"
},
  
];

class City{
  final int ?cityId;
  final String?provinceName;
  final String?cityName;
  final int ?provinceId;
  const City({
    this.cityId, 
    this.cityName,
    this.provinceId,
    this.provinceName
  });
  
  @override
  String toString()=>'City{name:$cityName,provinceName:$provinceName}';
  
  factory City.fromJson(Map<String,dynamic>json){
    return City(
      cityId: int.parse(json['cityId']as String), 
      cityName: json['cityName'] as String,
      provinceId: int.parse(json['provinceId'] as String), 
      provinceName: json['provinceId'] as String 
    );
  }
}

void main(){
  List<City>allCities=rawData.map((rawData)=>City.fromJson(rawData)).toList();
  print(allCities.toString());
  
//  لیست شهر های استان اصفحان
  List<City>esphahanCities=allCities.where((element)=>element.provinceId==10).toList();
  print(esphahanCities.toString());
}