PHP accessing deeper object properties through string variable

Question

I have this simple function to not get any warnings when a property doesn't exist:

function getProperty($object, $property, $default = ""){
    if (is_object($object) && isset($object->$property)) return $object->$property;

    return $default;
}

That works great for something like this:

$o = new stdClass();
$o->name = "Peter";

$name = getProperty($o, 'name', 'No name');
$email = getProperty($o, 'email', 'No email');

That will return $name = 'Peter' and $email = 'No email'.

Now I want to do the same for the following object:

$o = new stdClass();
$o->wife = new stdClass();
$o->wife->name = "Olga";

getProperty($o, "wife->name", "No name");

This doesn't work as the function will now try to get the property literally named "wife->name" which doesn't exist.

Is there a way I can adjust this function so it can go arbitrarily deep into an object?

You can use getProperty($o->wife, 'name', 'No Name') with your existing code but you will have to assert that $o->wife exists. — Scopey
– Scopey, Commented Apr 4, 2016 at 3:57
That's exactly the issue. Every level on the way down could or could not exist. That's why I want this check. — Coo
– Coo, Commented Apr 4, 2016 at 4:47

Chetan Ameta · Accepted Answer · 2016-04-04 04:57:54Z

1

You can explode argument by -> and iterate it. try below solution:

function getProperty($object, $property, $default = ""){

    $properties = explode('->', $property);

    if($properties){
        foreach($properties as $val){
            if(isset($object->$val)){
                $object = $object->$val;
            } else{
                break;
            }
        }
    }

    if (!is_object($object) && $object) return $object;

    return $default;
}

$o = new stdClass();
$o->name = "Peter";

echo $name = getProperty($o, 'name', 'No name'); //output: Peter
echo $email = getProperty($o, 'email', 'No email'); //output: No email

$o = new stdClass();
$o->wife = new stdClass();
$o->wife->name = "Olga";

echo getProperty($o, "wife->name", "No name"); //output: Olga

answered Apr 4, 2016 at 4:57

Chetan Ameta

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1 Comment

Coo Over a year ago

That's very clever. Resetting $object to be the next one down the line. It works exactly as intended, goes arbitrarily deep and could even be simply adjusted to account for assoc arrays instead of objects as well. Thank you!

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