Echo category name if checked in a list of posts

Question

I am trying to get all categories that are attached to a custom post type in Wordpress.

I have a custom post type named doc_pipeline and a custom taxonomy named tax_pipeline. I have been searching for hours on this and I can't put the right functions together to make this happen. To repeat I need to get a category name that is attached to the custom post type only if it is checked. Should be fairly simple, but I am quite lost.

    $args = array(
        'post_type' => 'doc_pipeline',
        'taxonomy' => 'tax_pipeline',
        'posts_per_page' => -1
    );

    $categories = get_categories( $args );

    $posts = get_posts($args);

foreach($posts as $post) {
   var_dump(is_object_in_term( $post->ID, 'tax_pipeline', 'doc_pipeline'));
}

Answer 1

To get the category name of the post by post id you should use like this. you already have post ID so, you don't have to pass post type.

$cat_array = wp_get_post_terms($post->ID, 'tax_pipeline', array('fields'=>'names'));

and

// To Remove dublicate category from loop, try this.

$unique_terms = array(); // instead of $dupe = 0;

while ( $wp_query->have_posts() ) : $wp_query->the_post();
global $post;
    //Ok, Then you have to use like this in your loop.
    $cat_array  = wp_get_post_terms( $post->ID, 'tax_pipeline', array( 'fields' => 'all' ) );
    foreach( $cat_array as $term ) :
        if( ! in_array( $term->term_id, $unique_terms ) ):
            array_push( $unique_terms, $term->term_id );
            echo $term->name;
        endif;
    endforeach; 
endwhile;