使用简单 HTML DOM 解析器按 ID 查找表

Question

我去年写了一个数据库播种器，用于抓取一个统计网站。重新访问我的代码后，它似乎不再起作用，我对原因感到有些困惑。 $html->find() 应该返回找到的元素数组，但它似乎只在使用时才找到第一个表。

根据文档，我尝试使用 find() 并指定每个表的 ID，但这似乎也失败了。

$table_passing = $html->find('table[id=passing]');

谁能帮我弄清楚这里出了什么问题？我不知道为什么这些方法都不起作用，页面源清楚地显示了多个表和 ID，这两种方法都应该起作用。

private function getTeamStats()
{
    $url = 'http://www.pro-football-reference.com/years/2016/opp.htm';
    $html = file_get_html($url);

    $tables = $html->find('table');

    $table_defense = $tables[0];
    $table_passing = $tables[1];
    $table_rushing = $tables[2];

    //$table_passing = $html->find('table[id=passing]');

    $teams = array();

    # OVERALL DEFENSIVE STATISTICS #
    foreach ($table_defense->find('tr') as $row)
    {
        $stats = $row->find('td');

        // Ignore the lines that don't have ranks, these aren't teams
        if (isset($stats[0]) && !empty($stats[0]->plaintext))
        {
            $name = $stats[1]->plaintext;
            $rank = $stats[0]->plaintext;
            $games = $stats[2]->plaintext;
            $yards = $stats[4]->plaintext;

            // Calculate the Yards Allowed per Game by dividing Total / Games
            $tydag = $yards / $games;

            $teams[$name]['rank'] = $rank;
            $teams[$name]['games'] = $games;
            $teams[$name]['tydag'] = $tydag;
        }
    }

    # PASSING DEFENSIVE STATISTICS #
    foreach ($table_passing->find('tr') as $row)
    {
        $stats = $row->find('td');

        // Ignore the lines that don't have ranks, these aren't teams
        if (isset($stats[0]) && !empty($stats[0]->plaintext))
        {
            $name = $stats[1]->plaintext;
            $pass_rank = $stats[0]->plaintext;
            $pass_yards = $stats[14]->plaintext;

            $teams[$name]['pass_rank'] = $pass_rank;
            $teams[$name]['paydag'] = $pass_yards;
        }
    }

    # RUSHING DEFENSIVE STATISTICS #
    foreach ($table_rushing->find('tr') as $row)
    {
        $stats = $row->find('td');

        // Ignore the lines that don't have ranks, these aren't teams
        if (isset($stats[0]) && !empty($stats[0]->plaintext))
        {
            $name = $stats[1]->plaintext;
            $rush_rank = $stats[0]->plaintext;
            $rush_yards = $stats[7]->plaintext;

            $teams[$name]['rush_rank'] = $rush_rank;
            $teams[$name]['ruydag'] = $rush_yards;
        }
    }

Answer 1

我从不使用simplexml 或其他派生词，但是当使用XPath 查询来查找诸如ID 之类的属性时，通常会以@ 为前缀，并且应该引用该值-因此对于您的情况，它可能是

$table_passing = $html->find('table[@id="passing"]');

---

使用标准的 DOMDocument 和 DOMXPath 方法，问题在于源代码中的实际表是 "commented out" - 因此 html cmets 的简单字符串替换启用以下工作 - 这可以很容易地适应原始代码。

$url='http://www.pro-football-reference.com/years/2016/opp.htm';

$html=file_get_contents( $url );
/* remove the html comments */
$html=str_replace( array('<!--','-->'), '', $html );

libxml_use_internal_errors( true );
$dom=new DOMDocument;
$dom->validateOnParse=false;
$dom->standalone=true;
$dom->strictErrorChecking=false;
$dom->recover=true;
$dom->formatOutput=false;
$dom->loadHTML( $html );
libxml_clear_errors();  



$xp=new DOMXPath( $dom );
$tbl=$xp->query( '//table[@id="passing"]' );

foreach( $tbl as $n )echo $n->tagName.' > '.$n->getAttribute('id');

/* outputs */
table > passing