You might find this code helpful. I wrote this as a Perl version of a Python lab assignment. If there is no entry for a column, you get undef. HTML::TableExtract might not be the most up to date module for this, however, this worked well. Multiple tables can be in the html page, here there is only one.

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

use HTML::TableExtract;

my @db;

my $raw_html = do {
    open my $in, '<', 'lab8input.txt' or die "Can't open lab8input.txt
+ $!";
    local $/ = undef;
    <$in>;
};

my $te = new HTML::TableExtract( headers => ['Course',
                                             'Course\s+Name',
                                             "Fall",
                                             "Winter",
                                             "Spring",
                                             "Summer"]);              
+                            

$te->parse($raw_html);

# Examine all matching tables
foreach my $ts ( $te->table_states ) 
{
   # print "Table (", join(',', $ts->coords), "):\n"; # there's only o
+ne table!
   
   foreach my $row ( $ts->rows ) 
   {
      @$row = map{$_//=''}@$row;  #set undef cols to empty string
      my @quarter_flags = (@$row)[-4..-1];
      my @quarters;
      push @quarters,'Fall'   if shift @quarter_flags;
      push @quarters,'Winter' if shift @quarter_flags;
      push @quarters,'Spring' if shift @quarter_flags;
      push @quarters,'Summer' if shift @quarter_flags;
      
      push @db, [@$row[0], @$row[1], join(',',@quarters)];
     # print join( ',', @$row ), "\n";
   }
 }

print Dumper \@db;

__END__

@db looks like this:  3 columns: Course,Name,Quarters offered (if any 
+listed)
          [
            'CIS 95B',
            'Project Planning and Control - A Practicum',
            'Fall,Spring'
          ],
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