use strict;
use warnings;
use HTML::Table;
use HTML::TableExtract;

my $tbltext = <<'END_TBL';
<table>
    <tr><td>1</td><!-- deleted! <td>2</td>!--><td>3</td><td>4</td></tr>
    <tr><td>one</td><td>two</td><td>three</td></tr>
</table>
END_TBL

my $tableEx = HTML::TableExtract->new ();

$tableEx->parse ($tbltext);

my @rows = $tableEx-> rows ();

for my $row (@rows) {
    next if @$row < 3; # Not interested in short rows
    
    $row->[2] = 'newText';
}

my $tableOut = HTML::Table->new ();

$tableOut->addRow (@$_) for @rows;
$tableOut->print ();

##</code><code>##

<table>
<tr><td>1</td><td>3</td><td>newText</td></tr>
<tr><td>one</td><td>two</td><td>newText</td></tr>
</table>