title: How to form an array for query from URL with multiple parameters
body: <p>This is on the second page of a filter that I am making, on the first page the user is able to select check-boxes. The values of the check-boxes get passed to the second page by parameters in the URL: 
  <code>filter-result/?mytaxonomy=myterm&amp;mytaxonomy=myotherterm</code>
  How to form an array of this data to use in a (WP) query?</p>
  
  <p>I'm able to display the data from the URL by doing this:</p>
  
  <pre><code>    if( isset( $_GET['mytaxonomy'] ) ){
          foreach( $_GET['mytaxonomy'] as $term ){
              echo $term . '&lt;br&gt;';
          }
      }
  </code></pre>
  
  <p>I am also able to query posts (custompost-type):</p>
  
  <pre><code>    $query = new WP_Query( array(
          'post_type' =&gt; 'mycustomposttype',
          'tax_query' =&gt; array(
              array(
                  'taxonomy' =&gt; 'mytaxonomy',
                  'field' =&gt; 'slug',
                  'terms' =&gt; array( 'myterm', 'myotherterm' ),
                  'operator' =&gt; 'AND',
              ),
          ),
      ) );
  </code></pre>
  
  <p>I want to pass the data from <code>$_GET['mytaxonomy']</code> to <code>'terms' =&gt; array( *inside here* )</code>. </p>
  
  <p>When I use <code>print_r ($_GET['mytaxonomy']);</code> the result is <code>Array ( [0] =&gt; myterm )</code>, All correct. I guess I just need to form the array to <code>'a', 'b'</code> to work in the WP query. How can I achieve this?</p>