PHP array keys values

I have an array like this

$data = array(
    "some"   => "163",
    "rand"  => "630",
    "om"    => "43",
    "words" => "924",
    "as"    => "4",
    "keys"  => "54"
);

How can I get each set's key associated with their values like this:

foreach ($data as $stuff){
  $this->$stuff["key"] = $stuff["value"];
}