Laravel:视图索引中未定义的偏移量.blade.php

在我的路线中，我把这条路线定义为：

// app/routes.php
Route::resource('CharacterController');

控制器中的对应方法是：

// app/controllers/CharacterController.php
public function index(){
    $characters = Character::all();
    $houses = House::all();
    return View::make('characters.index')->with(array('characters'=>$characters, 'houses' => $houses));
}

最后，在以下观点中：

// app/views/characters/index.blade.php
#this fires an error:
{{ $houses[$characters->house_id]->name }}
# at the same time this gives correct result: 
{{ $houses[1]->name }}
# and this IS equal to 1:
{{ $characters->house_id }}