<?php
$ary=array();
$tmp=5001;
$start=array_sum(explode(' ',microtime()));
while(--$tmp)
{
$ary[]=$tmp;
count($ary);
}
echo '<br />'.(array_sum(explode(' ',microtime()))-$start);
$ary=array();
$tmp=5001;
$start=array_sum(explode(' ',microtime()));
while(--$tmp)
{
$ary[]=$tmp;
sizeof($ary);
}
echo '<br />'.(array_sum(explode(' ',microtime()))-$start);
?>
0.30639410018921
0.096214056015015
:D