在Laravel中将eloquent结果转换为关联数组

How can convert the result from eloquent to associative array. I need to select tow column and have one as key and another as value. Here is the closet I got, however the value is an array. I want it to be only "my_value" column.

$array = Post::select('my_key','my_value')->get()->keyBy('my_key')

You should use lists (Laravel 5.1) or pluck (Laravel 5.2+):

$array = Post::lists('my_value', 'my_key');

or

$array = Post::pluck('my_value', 'my_key');

I found a way to do so, I'm not sure whether it's proper way to do this performance wise though...

$array = Post::select('my_key','my_value')->get()->mapWithKeys(function ($item) {
            return [$item['my_key'] => $item['my_value']];
        })->toArray();