Array Append
Append, or array append, is an array operation, which adds an element at the end of the array. It is also called a push.
There are two operators for this feature ; the [] operator, which has to be placed after a variable or member. There is also the array_push() function, which is available as a callback, unlike the operator.
The opposite operation is a pop, with the function array_pop(). array_unshift() is the append at the beginning of the array.
<?php
$array = [1, 2, 3];
$array[] = 4;
$array []= 5; // Same as above, with a notation similar to a short assignation
array_push($array, 6);
// $array === [1, 2, 3, 4, 5, 6];
?>