Extract First Gallery from a post

gallery-extract.php

<?php
// Extract the first gallery from a page/post
function  first_gallery_401($id = false, $echo = true)  {
    global $post;
    if(!$id) $id = $post->ID;
    if ( $gallery = get_post_gallery() ) :
        add_filter( 'post_gallery', 'remove_the_first_gallery' );
        if($echo):
            echo $gallery;
        else:
            return $gallery;
        endif;
    endif;
    return false;
}
// Remove the gallery from the post
function remove_the_first_gallery( $output, $attr ) {
    // We only want to remove the first gallery so let's turn off this filter
    remove_filter( 'post_gallery', 'remove_the_first_gallery' );
    $output = '<!-- gallery 1 was here -->';   // Must be non-empty.
    return $output;
}