Create array of specific substrings - php

Question

We use a custom CMS, build with PHP MySQL
I have a customer who embeds youtube videos in the content of the site. That is one string, that he can edit with CKeditor. That all works just fine.
He now wants to have those videos displayed on a different location within the same page.
I do not want to create a separate input field in the system just for this, for multiple reasons.
The solution I need is this:
I want to extract the (multiple) < iframe >youtube blah blah< /iframe > from the content string and create an array of iframe strings. Then I can display them elsewhere on the page.
For not displaying videos in the original content location I can use preg_replace to strip the iframes out of the content string.
I however have no idea how to fetch those substrings and form that new array in PHP.
Hope you have an idea and that my explanation is clear.
EDIT after getting the answer from Michel
The complete code I am using now:
$string = '<iframe>youtube iframe</iframe>Some cool text in between blahblah<iframe>moreyoutube</iframe>';
//catch the iframes
$iframe=array();
$parts=explode('<iframe',$string);
if (count($parts) > 1){ //make sure a string without iframes does not end up in the array
foreach($parts as $p){
if( strpos($p,'youtube') !== false ){
$v=explode('</iframe>',$p);
$iframe[]= '<iframe'.$v[0].'</iframe>';
}
}
}
//strip out iframes
$string = preg_replace('/<iframe(.*?)<\/iframe>/', '', $string);
This will give you a string without iframes, and an array of iframes to display seperately.
Thanks to Michel for the answer.

Answer 1

One way of doing it:
explode the content string on <iframe>.
Loop the resulting array and look with strpos for the word youtube (to rule out other iframes on the page).
If you find any, add <iframe> and </iframe> to the result
$string='<div>blabla</div><iframe src="youtube.org.com.uk.sk"></iframe><div>blahblah</div>';
$iframe=array();
$parts=explode('<iframe',$string);
foreach($parts as $p){
if( strpos($p,'youtube') !== false ){
$v=explode('</iframe>',$p);
$iframe[]= '<iframe'.$v[0].'</iframe>';
}
}