[WP][PHP] Split first paragraph from main content, display it elsewhere

manage_paragraphs.php

<?php
	
	// Grab the first paragraph, show it where you need it, then take the rest of the content and remove the first paragraph and show it elsewhere
	// The script uses WordPress functions/content but can be used in any PHP script, just replace the WP functions

	// First Paragraph
    global $post;
    $p1 = wpautop( $post->post_content );
	$p1 = substr( $p1, 0, strpos( $p1, '</p>' ) + 4 );
	//$p1 = strip_tags($p1, '<a><strong><em><h3><h2><i>'); // in case you need to remove some tags, add the ones you want to KEEP here
?>

<div class="first_paragraph">
	<?php echo $p1; ?>
</div>

<?php
    // Second paragraph onwards
    $allp = wpautop ( $post->post_content );
	$allp = substr( $allp, strlen($p1));
?>

<div class="rest_of_content"> 
	<?php echo $allp; ?>
</div>