PHP簡單的HTML DOM找到后找到

Question

如何在find循環中執行find循環？ 我一直在獲取PHP Notice: Trying to get property of non-object在行echo $li->find('span')->innertext; PHP Notice: Trying to get property of non-object echo $li->find('span')->innertext; 。

// get the html
$html = file_get_html('<url>');

// loop through the required element
foreach($html->find('body') as $body){

    // loop through the selected element
    $lis = $body->find('li');

    foreach($lis as $li){
        // loop through li to get the required span
        echo $li->find('span')->innertext;
    }
}

我正在使用簡單HTML Dom http://simplehtmldom.sourceforge.net/manual.htm

Answer 1

您收到錯誤消息，因為查找span返回一個數組；如果使用第二個參數，則返回null

// get the html
$html = file_get_html('<url>');

// loop through the required element
foreach($html->find('body') as $body){

// loop through the selected element
$lis = $body->find('li');

    foreach($lis as $li){
        // loop through li to get the required span
        $span = $li->find('span', 0);
        if(null !== $span){
            echo $span->innertext;
        }
     }
}

而且我認為您可能要檢查遍歷dom

Answer 2

您可以嘗試以下操作：

// get the html
$html = file_get_html('<url>');

// loop through the required element
foreach($html->find('li > span') as $span){

    echo span->innertext;
}

下面提供了一些示例（來自站點）以闡明您的理解：

// Find all <li> in <ul> 
$es = $html->find('ul li');

// Find Nested <div> tags
$es = $html->find('div div div'); 

// Find all <td> in <table> which class=hello 
$es = $html->find('table.hello td');

// Find all td tags with attribite align=center in table tags 
$es = $html->find(''table td[align=center]');

您應該閱讀文檔以更好地理解。 另外，在訪問任何屬性之前檢查項目，例如： if ($someItem)等。