foreach (@new_line) {
	print $_, "\n";
	my @ju = split ,@new_line;

		$self->{code}{$ju[0]} = {
			event => $ju[1],
			month => $ju[2],
			am => $ju[3],
			pm => $ju[4],
	}
	}
	
	print Dumper $self->{code};
}


Output:

$VAR1 = {
          'MN739' => {
                       'am' => '3.98',
                       'event' => 'U710',
                       'month' => 'Jul',
                       'pm' => '1.83'
                     },
          'RF858' => {
                       'event' => 'U888',
                       'am' => '7.22',
                       'pm' => '4.20',
                       'month' => 'Dec'
                     },
          'VS524' => {
                       'month' => 'Aug',
                       'pm' => '1.78',
                       'am' => '5.22',
                       'event' => 'U14'
                     },
          'BD110' => {
                       'event' => 'U804',
                       'am' => '0.04',
                       'pm' => '9.71',
                       'month' => 'Jul'
                     },
          'OA322' => {
                       'month' => 'Jul',
                       'pm' => '9.23',
                       'am' => '9.93',
                       'event' => 'U19'
                     }
        };