PHP => ขอคำแนะนำเรื่อง ให้แสดงผล "จำนวนบันทัดที่กำหนด"

$x="kasdf, sdjfsd, asdfjsdf ,asdfasf, sdfasdf, asdfsdfsdf";
$b=split(",", $x, 5); unset($b[5]);
echo implode('<br>', $b);

<?php 
$x="kasdf, sdjfsd, asdfjsdf ,asdfasf, sdfasdf, asdfsdfsdf";
$x=str_replace(',','<br>',$x);

 for ($i=0; $i<=5; $i++) {
  echo $x;
}
?> 

<?php 
$x="kasdf, sdjfsd, asdfjsdf, asdfasf, sdfasdf, asdfsdfsdf";
$b=split(",", $x, 5); unset($b[5]);
echo implode('<br>', $b);
 ?>

<?php 
$x="kasdf, sdjfsd, asdfjsdf ,asdfasf, sdfasdf, asdfsdfsdf";

for($i=0; $i<5; $i++)
{
	$b = explode(",", $x);
	echo $b[$i]."<br>";
}
 ?>

<?php 
$x="kasdf, sdjfsd, asdfjsdf ,asdfasf, sdfasdf, asdfsdfsdf";
$b = explode(",", $x);
for($i=0; $i<5; $i++) { echo $b[$i]."<br>"; }
?>

$x="kasdf, sdjfsd, asdfjsdf ,asdfasf, sdfasdf, asdfsdfsdf";
$b = explode(",", $x);
for($i=0; $i<5; $i++)
{

echo $b[$i]."<br>";
}