PHP dom解析代码echos每个语句三次而不是一次

Question

I have this code to extract statements from a multiple pages of a forum site. it works great except it prints each statement thrice instead of once. I checked each and every line still i don't understand why.

My code goes as:

<?php
    set_time_limit(3600);
    $i = 0;

    while($i < 100)
    {
        $e = 839303 - $i;

        require_once('dom/simple_html_dom.php'); 
        $html =file_get_html('http://www.usmleforum.com/files/forum/2017/1/'.$e.'.php');

        foreach ($html->find("tr") as $row)
        {
            $element = $row->find('td.Text2',0);

            if ($element == null) { continue; }

            $textNode = array_filter($element->nodes, function ($n)
            {
                 return $n->nodetype == 3;        //Text node type, like in jQuery     
            });

            if (!empty($textNode))
            {
                $text = current($textNode);
                echo $text."<br>"; 
            }
        }

        $i++;
    }
?>

In other hand, if the site that we are extracting contains more than on statements of the hidden somewhere, can we only ask the parser to echo once?

Any help is appreciated..

Trying to parse user details...but not working,, kinda skipping..

//User
    $element = $html->find('td.FootNotes2',0);
    if ($element == null) { continue; }
    $textNode = array_filter($element->nodes, function ($n) {
    return $n->nodetype == 3;        
    });
    if (!empty($textNode)) {
    $text = current($textNode);
    echo $text."<br><hr><hr>"; 
    }

Answer 1

The reason you are getting 3 outputs of the same text is because of the selection being made and the HTML structure of the page. The entire site is made up of nested tables, and so what is happening is the used query is finding all <tr>...</tr> tags on the entire page. Then looping through every tr tag and looking for the first td.Text2 which also shows up in the HTML multiple times on the pages, example.

This is going to be a tricky crawl given the structure of the HTML and you may be better off searching for only td.Text2 and grabbing the first one on the page instead. Below is an example of this solution.

Something like seems to work, but the pages are not the same throughout the loop so the results are a little weird:

<?php
require_once('dom/simple_html_dom.php');
set_time_limit(3600);
$i = 0;

while ($i < 100) {
    $e = 839303 - $i;
    $html = file_get_html('http://www.usmleforum.com/files/forum/2017/1/'.$e.'.php');
    $i++;

    $element = $html->find('td.Text2',0);

    if ($element == null ) { continue; }

    $textNode = array_filter($element->nodes, function ($n) {
         return $n->nodetype == 3;        //Text node type, like in jQuery
    });

    if (!empty($textNode)) {
        $text = current($textNode);
        echo $text."<br>";
    }

    // Getting User/Author
    $parent = $element->parent()->parent();
    $element = $parent->find('td.FootNotes2',1);
    if ($element == null) { continue; }
    $textNode = array_filter($element->nodes, function ($n) {
      return $n->nodetype == 3;
    });
    if (!empty($textNode)) {
      $text = current($textNode);
      echo $text."<br><hr><hr>";
    }
}