Question

How do I get the maximum length for each column using Nokogiri?

Example HTML:

<table>
 <tr>
  <td>ONE</td><td>TWO</td><td>THREE</td>
 </tr>
 <tr>
  <td>Monaco</td><td>Bangkok</td><td>Thailand</td>
 </tr>    
</table>

The result would the string length inside each <td>.

<td>one</td> => 3
<td>two</td> => 3
<td>three</td> => 5
....

Answer 1

First you would map the length of tr/td:

lengths = doc.search('tr').map{|tr| tr.search('td').map{|td| td.text.length}}
=> [[3, 3, 5], [6, 7, 8]]

transpose that to get columns and get just the max from each:

lengths.transpose.map &:max
=> [6, 7, 8]