Array keys can only be strings or integers, the rest will be casted to integers
$array = [true => "a", 1 => "b", '1' => "c", 1.8 => "d"];
print_r($array); // Array ([1] => "d")Array to variables
list($a, $b, $c) = ["Value 1", "Value 2", "Value 3"];
echo $a; // Value 1
echo $b; // Value 2
// ...