How to parse tables without id on HTML using HtmlAgilityPack - html

Question

I have a problem getting the values of a table in HTML cause it doesn't have a ids. I need to get all the values on the second column and keep them into an array. I am using HtmlAgilityPack and my problems comes when selecting nodes:
Dim doc As HtmlDocument
Dim web As New HtmlWeb()
Dim str As String
doc = Web.Load("http://www.dietas.net/tablas-y-calculadoras/tabla-de-composicion-nutricional-de-los-alimentos/carnes-y-derivados/aves/pechuga-de-pollo.html#")
Dim nodes_filas As HtmlNode() = doc.DocumentNode.SelectNodes("//table[#id='']//tr").ToArray
Dim nodes_columnas As HtmlNode() = doc.DocumentNode.SelectNodes("//td").ToArray
For Each row As HtmlNode In nodes_filas
For Each column As HtmlNode In nodes_columnas
str = column.InnerHtml & vbCrLf
Next
Next
This is the table:
<table cellspacing="1" cellpadding="3" width="100%" border="0">
<tr>
<td colspan="2" style="font-size:13px;color:#55711C;padding-bottom:5px;">Aporte por ración</td>
</tr>
<tr style="background-color:#EBEBEB">
<td width="125">Energía [Kcal]</td>
<td class="td_right">145,00</td>
</tr>
<tr>
<td>Proteína [g]</td>
<td class="td_right">22,20</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>Hidratos carbono [g]</td>
<td class="td_right">0,00</td>
</tr>
<tr>
<td>Fibra [g]</td>
<td class="td_right">0,00</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>Grasa total [g]</td>
<td class="td_right">6,20</td>
</tr>
<tr>
<td>AGS [g]</td>
<td class="td_right">1,91</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>AGM [g]</td>
<td class="td_right">1,92</td>
</tr>
<tr>
<td>AGP [g]</td>
<td class="td_right">1,52</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>AGP /AGS</td>
<td class="td_right">0,79</td>
</tr>
<tr>
<td>(AGP + AGM) / AGS</td>
<td class="td_right"> 1,80</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>Colesterol [mg]</td>
<td class="td_right">62,00</td>
</tr>
<tr>
<td>Alcohol [g]</td>
<td class="td_right">0,00</td>
</tr>
<tr style="background-color:#EBEBEB">
<td>Agua [g]</td>
<td class="td_right">71,60</td>
</tr>
</table>

Answer 1

Sorry I don't have VB installed but C# version should be enough to give you an idea. You have td_right class, you can use either lambda or xpath to query it.
I like lambda/linq version more because I am familiar with linq, and I don't need to remember XPATH syntax.
Lambda:
public static bool HasClass(this HtmlNode node, params string[] classValueArray)
{
var classValue = node.GetAttributeValue("class", "");
var classValues = classValue.Split(' ');
return classValueArray.All(c => classValues.Contains(c));
}
var url = "http://www.dietas.net/tablas-y-calculadoras/tabla-de-composicion-nutricional-de-los-alimentos/carnes-y-derivados/aves/pechuga-de-pollo.html#";
var htmlWeb = new HtmlWeb();
var htmlDoc = htmlWeb.Load(url);
var nodes = htmlDoc.DocumentNode.Descendants("td").Where(_ => _.HasClass("td_right")).Select(_ => _.InnerText);
XPATH:
var nodes2 = htmlDoc.DocumentNode.SelectNodes("//td[#class='td_right']");