Question

I’m trying to take an HTML document and group it into sections base on header tags using HTML Agility
Here’s what the raw HTML looks like

<h3>Header 1</h3>
<p>Text...</p>
<p>More Text...</p>
<h3Header 2</h3>
<p>Text...</p>
<p>More Text...</p>
<p>Even more Text...</p>
<h3>Header 3</h3>
<p>Some Text...</p>

and I want to have it end up something like this after I group it

<div id="header_1">
  <h3>Header 1</h3>
  <p>Text...</p>
  <p>More Text...</p>
</div>

<div id="header_2">
  <h3Header 2</h3>
  <p>Text...</p>
  <p>More Text...</p>
  <p>Even more Text...</p>
</div>

<div id="header_3">
  <h3>Header 3</h3>
  <p>Some Text...</p>
</div>

or like this

<h3>Header 1</h3>
<div id="header_1">
  <h3>Header 1</h3>
  <p>Text...</p>
  <p>More Text...</p>
</div>


<h3Header 2</h3>
<div id="header_2">
  <p>Text...</p>
  <p>More Text...</p>
  <p>Even more Text...</p>
</div>

<h3>Header 3</h3>
<div id="header_3">
  <p>Some Text...</p>
</div>

HTML Agility is great, but if anyone knows another way to accomplish this, that would be awesome!

Answer 1

It’s quite easy could be done with AgilityPack. First you need to get all the top <h3>s, create a <div> before (or after) each <h3>, then iterate through the following siblings of the current <h3> until the next <h3> or end of siblings found, and finally move these nodes into newly created <div>:

var h3s = doc.DocumentNode.SelectNodes("h3");
var idx = 1;
foreach (var h3 in h3s)
{
    var div = HtmlNode.CreateNode(string.Format("<div id='header_{0}'></div>", idx++));
    h3.ParentNode.InsertBefore(div, h3);
    var group = new List<HtmlNode> { h3 };

    for (var next = h3.NextSibling; next != null && next.Name != "h3"; next = next.NextSibling)
        group.Add(next);

    foreach (var item in group)
    {
        item.Remove();
        div.AppendChild(item);
    }
}

This will get you something like (I corrected <h3Header 2</h3> from your source):

<div id='header_1'>
  <h3>Header 1</h3>
  <p>Text...</p>
  <p>More Text...</p>
</div>
<div id='header_2'>
  <h3>Header 2</h3>
  <p>Text...</p>
  <p>More Text...</p>
  <p>Even more Text...</p>
</div>
<div id='header_3'>
  <h3>Header 3</h3>
  <p>Some Text...</p>
</div>