Benchmark: PHP Reverse Array while vs. for vs. foreach

Sunday, April 8^th, 2012. 0 comments

When looping through an array in reverse and wondering which was faster while finding nothing on Google, I put this benchmark together.

Function	Time	Comparison
`while()`	0.921 seconds	(38% faster)
`for()`	0.916 seconds	(38.4% faster)
`for()` optimized	0.793 seconds	(46.6% faster)
`foreach()`	1.486 seconds

Here is the code:

<?php
 
$test_array = array(0,1,2,3,4,5);
 
function getmicrotime()
{
	list($usec, $sec) = explode(' ',microtime());
	return ((float)$usec + (float)$sec);
}
 
$time_start = getmicrotime();
for ($i=0; $i<1000000; $i++)
{
	$j = count($test_array)-1;
 
	while ($j >= 0)
	{
		$test_array[$j];
 
		$j--;
	}
}
echo 'while() :: '.number_format(getmicrotime()-$time_start,3).' seconds<br/>';
 
$time_start = getmicrotime();
for ($i=0; $i<1000000; $i++)
{
	$length = count($test_array)-1;
 
	for ($j=$length; $j>=0; $j--)
	{
		$test_array[$j];
	}
}
echo 'for() :: '.number_format(getmicrotime()-$time_start,3).' seconds<br/>';
 
$time_start = getmicrotime();
for ($i=0; $i<1000000; $i++)
{
	for ($j=count($test_array)-1; $j>=0; $j--)
	{
		$test_array[$j];
	}
}
echo 'for() optimized :: '.number_format(getmicrotime()-$time_start,3).' seconds<br/>';
 
$time_start = getmicrotime();
for ($i=0; $i<1000000; $i++)
{
	$reversed_array = array_reverse($test_array, true);
 
	foreach ($reversed_array as $key=>$value)
	{
		// Nothing
	}
}
echo 'foreach() :: '.number_format(getmicrotime()-$time_start,3).' seconds<br/>';
 
?>

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