Performance of array_shift and array_pop in PHP

We have confirmed that array_shift is much slower than array_pop in PHP.

Code:

<?
// Create an array with 100000 elements
$array = array();
for ($i = 0; $i < 100000; $i++) {
	$array[] = rand();
}
// Remove the last 1000 elements using array_pop
$start = microtime(true);
for ($i = 0; $i < 1000; $i++) {
	array_pop($array);
}
$stop = microtime(true);
printf(“array_pop takes %.5f seconds\n”, $stop – $start);
// Add back 1000 elements
for ($i = 0; $i < 1000; $i++) {
	$array[] = rand();
}
// Remove the first 1000 elements using array_shift
$start = microtime(true);
for ($i = 0; $i < 1000; $i++) {
	array_shift($array);
}
$stop = microtime(true);
printf(“array_shift takes %.5f seconds\n”, $stop – $start);
// Add back 1000 elements
for ($i = 0; $i < 1000; $i++) {
	$array[] = rand();
}
// Remove the first 1000 elements by reversing the array and popping 1000 elements
$start = microtime(true);
$array_rev = array_reverse($array);
for ($i = 0; $i < 1000; $i++) {
	array_pop($array_rev);
}
$stop = microtime(true);
printf(“array_reverse + array_pop takes %.5f seconds\n”, $stop – $start);
?>

Result:

array_pop takes 0.00089 seconds
array_shift takes 15.15544 seconds
array_reverse + array_pop takes 0.03934 seconds