(PHP 4, PHP 5)
array_shift вЂ” Shift an element off the beginning of array
array_shift() shifts the first value of the array off and returns it, shortening the array by one element and moving everything down. All numerical array keys will be modified to start counting from zero while literal keys won't be touched. If array is empty (or is not an array), NULL will be returned.
Example#1 array_shift() example
$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_shift($stack);
This would result in $stack having 3 elements left:
Array (  => banana  => apple  => raspberry )
and orange will be assigned to $fruit.