php：动态访问数组中的元素，即object属性

Question

i have an array as object property, $obj->_image = ['size' => '10']; and want to access it dynamically, like: (of course object initialized and exists, just skipped to make post shorter. print $obj->_image['size'] works like it should.)

$obj->get('image','size');

public function get($item,$element = '') {

if (!empty($element)) $element = "['$element']";
    $item = "_$item$element";

return $this->$item;
}

but get: Undefined property: obj::$_image['size']

tryed with {}, $$ - but looks like i am missing something..

Answer 1

Your problem is that you're trying to access a property that is an array, so you can't do it like you are doing it. Try this

class a
{

    private $_image = array("size" => 10);

    public function get($item, $element = '')
    {
        $prop = "_$item";
        if (property_exists(__CLASS__, $prop))
        {
            if (empty($element))
            {
                return $this->{$prop};
            }
            if(array_key_exists($element, $this->{$prop})){
                return $this->{$prop}[$element];
            }
        }
        throw new Exception("'$item' or '$element' don't exist");
    }

}

$a = new a;
echo $a->get("image", "size");

The problem with your code is that your property is an array, so you first need to access the array $this->{"_$prop"} and then the element within the array $this->{"_$prop"}[$el]