→ an array is an ordered, integer-indexed collection of objects (0-based)

$numbers = array(); // array vide
$numbers = array(2,4,6,8);
echo $numbers[0]; // 2

$mixed = array(2, "quatre", 6, array("x", "y", "z"));
echo $mixed[2]; // 6
echo "<pre>";
echo print_r($mixed[3]);
echo "</pre>";

$mixed[2] = "i";
$mixed[5] = "o"; // fonction mais $mixed[4] inexistant
$mixed[] = "o"; // peuple la prochaine case

PHP >= 5.4

$array = [1,2,3];