Change roles by regexp

Change roles in um_show_content shortcode

$posts = get_posts( array(
	'numberposts' => -1,
	'post_type' => 'any',
	'post_status' => 'publish'
) );

foreach ( $posts as $post ) {
	$content = preg_replace_callback( "/(\[um_show_content roles=\')(.*?)(\'\])/im", "um_custom_change_show_content_roles", $post->post_content );

	$post->post_content = $content;

	wp_update_post(array(
		'ID' => $post->ID,
		'post_content' => $post->post_content
	));
}


function um_custom_change_show_content_roles( $matches ) {
	$roles = $matches[2];
	$roles = explode( ',', $roles );

	$roles = array_map( function( $item ) {
		return 'um_' . $item;
	}, $roles );

	$roles = implode( ',', $roles );

	return $matches[1]. $roles . $matches[3];
}