Dart之类型转换

main() {
//  1、Number与String转换
  var num1 = 123;
  String str0 = num1.toString();
  print(str0 is String); //true
//2、String与Number转换
  String str = '123';
  var myNum = int.parse(str);
  print(myNum is int); //true
  String str2 = '123';
  var myNum2 = double.parse(str2);
  print(myNum2 is double); //true
//使用try catch处理异常
  var str3 = "";
  try {
    var myNum3 = double.parse(str3);
    print(myNum3);
  } catch (err) {
    print(err); //FormatException: Invalid double
    print(20); //20
  }
//  3、其他类型转换为Booleans类型
  var str4 = '';
  print(str4.isEmpty); //true
  var myNum4 = 2;
  print(myNum4 == 0); //false
  print(myNum4==null);//false
  var myNum5=0/0;
  print(myNum5.isNaN);//true
}