PHP concated string is blank at the end - php

Question

I am trying to concatenate a string in a loop and when its is over the string is blank (or whatever value it was before). I am not exactly sure what is happening but I can't seem to find a similar issue.
$toItem = "";
$recpItem = "";
if(is_array($to))
{
foreach($to as $key=>$email)
{
$recpItem = $recpItem.'<item><recip dn="'.$email.'" sa="'.$email.'" ra="'.$email.'" al="" rt="SMTP" id="" ao="3" rf="0" ei="0" uri=""/></item>';
$email = htmlentities($email);
$toItem = $toItem.'<item><Rcp DN="'.$email.'" EM="'.$email.'" RT="SMTP" AO="3"/></item>';
}
}

Answer 1

I would add the code to an array then implode() it:
$to = array(
'bob#gmail.com',
'sally#gmail.com'
);
if(is_array($to)){
$recpItem = array();
$toItem = array();
foreach($to as $email){
$recpItem[] = '<item><recip dn="'.$email.'" sa="'.$email.'" ra="'.$email.'" al="" rt="SMTP" id="" ao="3" rf="0" ei="0" uri=""/></item>';
$email = htmlentities($email);
$toItem[] = '<item><Rcp DN="'.$email.'" EM="'.$email.'" RT="SMTP" AO="3"/></item>';
}
$recpHtml = implode($recpItem);
$toHtml = implode($toItem);
echo $recpHtml;
echo '<hr />';
echo $toHtml;
}