Exchange Array

exchangeArray.php

<?php

$default = [
	'one' => null,
	'two' => null,
];

$incoming = ['two' => 123, 'three' => 345];

// only allow existing keys
$incoming = array_intersect_key($incoming, $default);

// fill up with defaults
$result = array_merge($default, $incoming);

// var_dump($result);

?>

method.php

<?php

public function exchangeArray($data)
{
    // defaults
    $default = array(
        'foo' => null,
    );
    
    // only allow existing keys
    $data = array_intersect_key($data, $default);
    
    // fill up with defaults
    $data = array_merge($default, $data);
    
    // $this->data = $data;
}

?>