func_vs_loop.php

<?php


for( $i = 0; $i < 1000000; $i++ )
{
	$el[] = md5('XX-'.$i);
}

$start = microtime(true);
foreach( $el as $hash )
{
	if( strpos($hash, 'a') === 0 ) 
		$aFinal[] = 'FOUND! '.$hash;
}
$time1 = microtime(true) - $start;

$start = microtime(true);
$bFinal = array_map(function($hash){
	return 'FOUND! '.$hash;
},array_filter($el, function($hash){
	return ( strpos($hash, 'a') === 0 );
}));
$time2 = microtime(true) - $start;

echo count($aFinal).' took '.round($time1,4)."\n";
echo count($bFinal).' took '.round($time2,4)."\n";
?>
----
62546 took 0.8741
62546 took 2.2139