<?php
$myArray['key']                = $value;
$myArray[/* key start */'key'] = $value;
$myArray[/* key start */'key'/* key end */] = $value;
$myArray  [  'key'  ]            = $value;
if ($array[($index + 1)] === true) {
} else if ($array  [ ($index + 1) ] === null) {
}
$array = [
    'foo' => 'bar',
    'bar' => 'foo',
];

$array = [];
?>