Get wordpress attachments ID's separated by commas of current post - php

Question

i have created custom post type named "Person" and i need to get all attachments ID's separated by commas of current post in loop.
Here i have a code that loops the "person" post type posts and code that shows every posts attachments ID's, but thing is that that those ID returns like this "2713271227112710" i need it to return seperated by commas like this "2713,2712,2711,2710"
Here is my code:
<?php
$args = array(
'post_type' => 'person',
'post_status' => 'publish',
'posts_per_page' => 24,
'order' => 'ASC'
);
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post(); ?>
<div class="col-md-4">
<div class="person">
<?php if ( $post->post_type == 'person' && $post->post_status == 'publish' ) {
$attachments = get_posts( array(
'post_type' => 'attachment',
'posts_per_page' => -1,
'post_parent' => $post->ID,
'exclude' => get_post_thumbnail_id()
) ); ?>
<?php
if ( $attachments ) {
foreach ( $attachments as $attachment ) {
$thumbimg = wp_get_attachment_url( $attachment->ID, 'full', false );
$attachment_id = attachment_url_to_postid( $thumbimg );
echo $attachment_id; //here outputs the attachemnts ID's of current post
}
}
}
?>
<?php echo do_shortcode( '[vc_images_carousel images="'.$attachment_id.'" img_size="large" speed="3000" autoplay="yes" hide_pagination_control="yes" hide_prev_next_buttons="yes" wrap="yes"]' ); ?>
<h3><?php the_title(); ?></h3>
<?php the_content(); ?>
</div>
</div>
<?php endwhile;
wp_reset_postdata(); ?>

Answer 1

Use implode in combination with an array_map, to return an array of IDs, and then convert it to a string of IDs, separated by a comma.
So instead of this:
foreach ( $attachments as $attachment ) {
$thumbimg = wp_get_attachment_url( $attachment->ID, 'full', false );
$attachment_id = attachment_url_to_postid( $thumbimg );
echo $attachment_id; //here outputs the attachemnts ID's of current post
}
Try this:
$attachment_ids = implode(',', array_map(function($attachment){
return $attachment->ID;
}, $attachments));
echo $attachment_ids;