wp_query return nothing

Question

I have custom post type 'book' and I also make taxonomy name best-book which. I want to filter taxonomy term but it doesn't work. I try to put echo and print_r to find where is my problem and I found that my $loop var return empty array. I also use this style in other pages and never have problem but I can't find why this happen? and how can I have fix it. here is the photo which show it return empty array here is my code

<?php $args = array( 'post_type'=>'book'); 
    loop = new WP_Query( $args );
    print_r($loop);
    while ( have_posts() ) : the_post();
    $post=the_post();

    $term_list = wp_get_post_terms($post_id, 'best-book', array("fields" => "all"));

    foreach($term_list as $term_single) 
}

?>

any idea would be appreciated.

Answer 1

You need to reference to your query, when starting the loop, otherwise it will show the posts found with the main query, instead of your custom query.

Try:

<?php

    $args = array( 'post_type'=>'book'); 
    $loop = new WP_Query( $args );

    // Start the loop for your custom query
    if($loop->have_posts() ) : while ($loop->have_posts() ) : $loop->the_post();

    the_title(); // just an example, output what you need here

    // Get the post terms
    $term_list = wp_get_post_terms($post->ID, 'best-book', array("fields" => "all"));

    // Iterate the terms, if found
    if($term_list) {
        foreach($term_list as $term_single) {
            echo $term_single;
        }
    }

    endwhile;

    // In case the query is empty
    else:

    // Debug the query
    echo '<pre>';
    var_dump($loop);
    echo '</pre>';

    endif;

?>