AngularJS Select默认值？

Question

AngularJS Select绑定的是对象：

$scope.cars = {
car01 : {brand : "Ford", model : "Mustang", color : "red"},
car02 : {brand : "Fiat", model : "500", color : "white"},
car03 : {brand : "Volvo", model : "XC90", color : "black"}
};

<select ng-model="selectedCar" ng-options="y.brand for (x, y) in cars"></select>

现在想给select一个默认值怎么设置呢？

Answer 1

<select ng-model="selectedCar" ng-options="y.brand for (x, y) in cars>
</select>

$scope.selectedCar = $scope.cars.car01;

这样就是默认选中第一项

Answer 2

<option>--please select--</option>