理解 wordpress的 Query Vars

$wp_query->query_vars['post_type']--会得到什么呢？

htps://codex.wordpress.org/WordPress_Query_Vars 

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function themeslug_query_vars( $qvars ) {
  $qvars[] = 'custom_query_var';
  return $qvars;
}
add_filter( 'query_vars', 'themeslug_query_vars' , 10, 1 );

https://codex.wordpress.org/Plugin_API/Filter_Reference/query_vars 

https://wordpress.org/support/topic/query_vars-filter-doesnt-work 

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// This would output '/client/?s=word&foo=bar'
echo esc_url( add_query_arg( 'foo', 'bar' ) );

https://codex.wordpress.org/Function_Reference/add_query_arg  

http://simonwheatley.co.uk/2009/02/adding-get-params-to-a-url-in-wordpress/

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<?php  $paged = get_query_var( 'paged', 1 );  ?>
<h1>Currently Browsing Page <?php echo $paged; ?></h1>

https://codex.wordpress.org/Function_Reference/get_query_var

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下面这个代码会出现什么？

 $args = array(
    'post_type' => 'post',
    'posts_per_page' => 2,
    'post_status' => 'publish'
);
 $args['prices'] = 22222222;
    $posts_query = new WP_Query($args);
 echo '<pre>'.print_r($posts_query,1).'</pre>';
 
 if ( isset($posts_query->query_vars['prices']) ) echo $posts_query->query_vars['prices']; 

可以通过 remove_query_arg 来移除。

如图：