csv-merge.php

<?php /* This changes the CSV into another CSV. But merges duplicated fields. */
$fh = fopen("clubexp.csv", "r");
$row = 0;
$clubs = array();

while (($data = fgetcsv($fh, 1000, ",")) !== FALSE) {
    // ID
    $club_id = $data[0];

    // Day
    $day = $data[17];
    // Times
    $start = $data[18];
    $end = $data[19];

    // Type of Group
    $type = $data[16] ? $data[16] .' - ' : '';

    // Format the date
    $date_line = $type . $day .': '. $start .' - '. $end;

    unset( $data[16] );
    unset( $data[18] );
    unset( $data[19] );

    $data = array_values( $data );

    if ( array_key_exists($club_id, $clubs) ) {
        $clubs[$club_id][16] .= "\n". $date_line;
    } else {
        $data[16] = $date_line;
        $clubs[$club_id] = $data;
    }
    $row++;
}

if (count($row) > 0) {
    $fh = fopen('clubexp_merged.CSV', 'w');
    if (!$fh) throw new Exception("Can't open CSV file for merged data");
    foreach($clubs as $club_id => $vals) {
        array_unshift($vals, $club_id);
        if (!fputcsv($fh, $vals)) throw new Exception("Can't write data to merged CSV file");
    }
    fclose($fh);
}

echo '<pre>';
print_r( $clubs );
echo '</pre>';