how to pass row id in href of a tag in codeigniter controller?

php codeigniter

PHP Snippet 1:

$data[$i]['action']='<a href="<?php echo base_url()?>/edit_tax/<?php echo $row["tax_id"]; ?>">Edit</a>';

PHP Snippet 2:

$data[$i]['action']='<a href="' . base_url() . '/edit_tax/' . $row["tax_id"] . '">Edit</a>';

PHP Snippet 3:

<?php
foreach($result as $row)
{
 $editurl = base_url() . 'admin/edit-user/' . $row['tax_id'];
 ?>
 <a href="<?php echo $editurl; ?>" class="edit-user" >Edit</a>
 <?php
}
?>

PHP Snippet 4:

$id =  $row["tax_id"];   
$data[$i]['action']='<a href="'.base_url().'/edit_tax/'.$id.'">Edit</a>';