也可以用作数组的对象

Question

All over the place I have an array with a few elements, for example:

$myItem = [ 'a' => 10, 'b' => 20 ]

But but I would like to replace it with a class

$myClass = new MyOwnClass( 10, 20 );

$a = $myClass->GetSomeValue(); // this is the old 'a'
$b = $myClass->GetSomeOtherValue(); // this is the old 'b'

but for practical reasons I still want to be able to call

$a = $myClass['a'];
$b = $myClass['b'];

Is something like that possible in php?

Answer 1

Therefore, there is an interface named ArrayAccess. You have to implement it to your class.

class MyOwnClass implements ArrayAccess {
    private $arr = null;

    public function __construct($arr = null) {
        if(is_array($arr))
            $this->arr = $arr;
        else
            $this->arr = [];
    }    

    public function offsetExists ($offset) {
        if($this->arr !== null && isset($this->arr[$offset]))
            return true;
        return false;
    }

    public function offsetGet ($offset) {
        if($this->arr !== null && isset($this->arr[$offset]))
            return $this->arr[$offset];
        return false;
    }

    public function offsetSet ($offset, $value) {
        $this->arr[$offset] = $value;
    }

    public function offsetUnset ($offset) {
        unset($this->arr[$offset]);
    }
}

Use:

$arr = ["a" => 20, "b" => 30];
$obj = new MyOwnClass($arr);

$obj->offsetGet("a"); // Gives 20
$obj->offsetSet("b", 10);
$obj->offsetGet("b"); // Gives 10