我只需要查询自定义帖子类型-即我的WP安装中的所有帖子类型，不包括帖子和页面。我用过get_post_types 要生成我要查询的所有自定义帖子类型的字符串，请执行以下操作：

$args=array(
    \'public\'                => true,
    \'exclude_from_search\'   => false,
    \'_builtin\'              => false
); 
$output = \'names\'; // names or objects, note names is the default
$operator = \'and\'; // \'and\' or \'or\'
$post_types=get_post_types($args,$output,$operator); 

// Loop thru the cpts and assign a related taxonomy to a variable
$posttypes_array = "";
foreach ($post_types  as $post_type ) {
    $posttypes_array .= "$post_type, ";
}
$posttypes_array = rtrim($posttypes_array, \', \');
echo $posttypes_array;

变量的输出$posttypes_array 是否为字符串：

\'puzzles\', \'quizzes\', \'challenges\', \'tales\', \'can_you_help\'

我的问题是，我无法使用此变量查询所有这些帖子类型，如下所示：

$buildArgsAllQuestions = array( // Add out new query parameters
    \'post_type\' => array($posttypes_array),
    //\'post_type\' => $posttypes_array,
    \'orderby\' => \'date\',
    \'order\' => \'DESC\',
);

仅当我将此行用于post\\u类型时，我对所有自定义帖子的查询才起作用：

\'post_type\' => array( \'puzzles\', \'quizzes\', \'challenges\', \'tales\', \'can_you_help\' ),

有人能告诉我如何使用这个变量吗$posttypes_array 或类似于查询所有自定义posttype的内容，如下所示：\'post_type\' => array($posttypes_array) ?

$posttypes_array = array();
foreach ($post_types  as $post_type ) {
    $posttypes_array[] = $post_type;
}

$buildArgsAllQuestions = array( // Add out new query parameters
    \'post_type\' => $posttypes_array,
    //\'post_type\' => $posttypes_array,
    \'orderby\' => \'date\',
    \'order\' => \'DESC\',
);