PHP Multidimensional Array Small doubt

PHP multi-dimensional array small problem

$families = array
(
  "Griffin" =>array
  (
  "Peter",
  "Lois",
  "Megan"
  ),
  "Quagmire" =>array
  (
  "Glenn"
  ),
  "Brown" =>array
  (
  "Cleveland",
  "Loretta",
  "Junior"
  )
);

Printing an element normally, that's what it says.
$families [Griffin][0],
But I've seen it written like this.
$families [Griffin[0]],
Excuse me, what's the difference?

------Solution--------------------

As the number four and the building of the example of the landlord, the second writing does have a problem
If you really want a value, try changing the array
$families = array
(
  "Griffin" =>array
  (
  "Peter",
  "Lois",
  "Megan"
  ),
  "Quagmire" =>array
  (
  "Glenn"
  ),
  "Brown" =>array
  (
  "Cleveland",
  "Loretta",
  "Junior"
  ),
  "Peter" =>9
);
  $Griffin =array (
  "Peter",
  "Lois",
  "Megan"
  );
Print_r ($families [' Griffin '][0]);
Print_r ($Griffin [0]);
Print_r ($families [$Griffin [0]]);

------Solution--------------------

Remove the subscript value named Fmilies array as [griffin],[0]
$families [Griffin][0],
Remove the subscript value named Fmilies array as [griffin[0]]
$families [Griffin[0]],

The values in the two different meanings [] are the following table in the array
The second way of writing in this example is wrong.
------Solution--------------------
2nd, the meaning of play to the same as the first

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