Эксперимент: сравнение скорости работы print и echo в PHP

 Код PHP:
print $a; print $b;
print $a.$b;
echo $a; echo $b;
echo $a.$b;
echo $a, $b;

 Код PHP:
function generateRandomString($length = 10) 
 { 
  $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; 
  $charactersLength = strlen($characters); 
  $randomString = ''; 
  for ($i = 0; $i < $length; $i++) 
   { 
    $randomString .= $characters[rand(0, $charactersLength - 1)]; 
   } 
  return $randomString; 
 }
$l1=100;
$l2=200;
$s1=generateRandomString($l1);
$s2=generateRandomString($l2).'<br />';
$msc1 = microtime(true);
print $s1;
print $s2;
$msc1 = microtime(true)-$msc1;
$msc2 = microtime(true);
print $s1.$s2;
$msc2 = microtime(true)-$msc2;
$msc3 = microtime(true);
echo $s1;
echo $s2;
$msc3 = microtime(true)-$msc3;
$msc4= microtime(true);
echo $s1.$s2;
$msc4 = microtime(true)-$msc4;
$msc5= microtime(true);
echo $s1,$s2;
$msc5 = microtime(true)-$msc5;
echo "1=".($msc1*1000)." ms<br />";
echo "2=".($msc2*1000)." ms<br />";
echo "3=".($msc3*1000)." ms<br />";
echo "4=".($msc4*1000)." ms<br />";
echo "5=".($msc5*1000)." ms<br />";