获取simpleXMLelement的子标签无效

Question

我正在尝试从XML文档中获取特定标记<zone></zone>。 我不能迭代$file变量来获得我需要的孩子。

我正在使用的代码是下一个：

$file=simplexml_load_file($transcriptionFile);
foreach($file->facsmile->surface->zone as $zone){
 //do things
}

对不起我的英文，提前谢谢。

var_dump（$ file）返回：

  object(SimpleXMLElement)[4]
  public '@attributes' => 
    array (size=1)
      'version' => string '5.0' (length=3)
  public 'teiHeader' => 
    object(SimpleXMLElement)[181]
      public 'fileDesc' => 
        object(SimpleXMLElement)[184]
          public 'titleStmt' => 
            object(SimpleXMLElement)[186]
              ...
          public 'publicationStmt' => 
            object(SimpleXMLElement)[187]
              ...
          public 'sourceDesc' => 
            object(SimpleXMLElement)[188]
              ...
      public 'encodingDesc' => 
        object(SimpleXMLElement)[185]
          public 'projectDesc' => 
            object(SimpleXMLElement)[191]
              ...
          public 'tagsDecl' => 
            object(SimpleXMLElement)[192]
              ...
          public 'appInfo' => 
            object(SimpleXMLElement)[193]
              ...
  public 'facsimile' => 
    object(SimpleXMLElement)[182]
      public 'surface' => 
        object(SimpleXMLElement)[209]
          public 'graphic' => 
            object(SimpleXMLElement)[210]
              ...
          public 'zone' => 
            array (size=28)
              ...
  public 'text' => 
    object(SimpleXMLElement)[183]
      public 'body' => 
        object(SimpleXMLElement)[239]
          public 'div' => 
            object(SimpleXMLElement)[240]
              ...