Will string concat case performant issue in PHP? - php

Question

I see some code like this in PHP
public function fetch()
{
$xml = '';
$xml .= '<' . '?xml version="1.0" encoding="utf-8"?' . '>' . "\n";
$xml .= '<rss version="2.0">';
$xml .= '<channel>';
$xml .= '<title>TEST</title>';
$xml .= '<description>TEST</description>';
foreach ($this->items as $item)
{
$xml .= '<item>';
$xml .= '<title>' . $item['title'] . '</title>';
$xml .= '<description>' . $item['body'] . '</description>';
$xml .= '</item>';
}
$xml .= '</channel>';
$xml .= '</rss>';
return $xml;
}
The code use a lots of stings concat (.=), do you think it is not a good way to do it ?
It look like will case unnecessary memory usage for me.
Those code was a part of "VIEW' of MCV, the function has already get the processed data in a array of "items". And the function is going to make the render.
Will you agree instead of
echo $this->fetch();
using a template file is better ? like this :
include('template.php');
and then in template.php :
<?xml version="1.0" encoding="utf-8">
<rss version="2.0">
<channel>
<title>TEST</title>
<description>TEST</description>
<?
foreach ($this->items as $item){
echo '<item>';
echo '<title>' . $item['title'] . '</title>';
echo '<description>' . $item['body'] . '</description>';
echo '</item>';
}
?>
</channel>
</rss>
I think the second approach would be better. Do you agree? or any other comment ?
Edit :
A user point out that using a template has it's lack too. So, when will you using the the template and when will not ? (those tutorials just always tell me i can use template anyways, i got a little confuse.)

Answer 1

Using a template is not necessarily better since it is an I/O operation (and I/O operation are often costly).
The concatenation in comparison is several times more performant. You could either remove the unnecessary concatenations (like the '<' . '?xml' part) or use HEREDOC / NOWDOC (http://php.net/manual/fr/language.types.string.php).
At the end of the day, it's mostly up to the developper's choice as long as the application is not purely performance-driven.
EDIT: as stated in comments, using an XML reader / writer class would prove more robust and increase maintainability.