title: woo commerce shop page apply custom filter
body: <p>I want to display particular authors' products on the shop page.
  but I don't know how can I do it I tried to do using the below code.</p>
  <pre><code>/**
     * Exclude products from a particular category on the shop page
  */
  function custom_pre_get_posts_query($q)
  {
  
   $user_id = 44;
  
  
  $args = array(
      'post_type'      =&gt; 'product',
      'posts_per_page' =&gt; -1,
      'fields'        =&gt; 'ids',
      'author' =&gt; $user_id
  );
  
  $loop = new WP_Query($args);
  
  echo '&lt;pre&gt;';
  print_r($loop-&gt;posts);
  echo '&lt;/pre&gt;';
  
  
  
  $tax_query = (array) $q-&gt;get('tax_query');
  
  $tax_query[] = array(
      'taxonomy' =&gt; 'product_cat',
      'field' =&gt; 'slug',
      'terms' =&gt; array('camisetas'), // Don't display products in the clothing category on the shop page.
      'operator' =&gt; 'NOT IN'
  );
  
  
  $q-&gt;set('tax_query', $tax_query);
  }
  add_action('woocommerce_product_query', 'custom_pre_get_posts_query');
  </code></pre>
  <p>now I get all products of a particular user id in my case it 44.
  but I don't know how to implement it in woo-commerce tax query.</p>