use League\Csv\Reader;

$csv = Reader::createFromPath('/path/to/your/csv/file.csv', 'r');

//get the first row, usually the CSV header
$headers = $csv->fetchOne();

//get 25 rows starting from the 11th row
$res = $csv->setOffset(10)->setLimit(25)->fetchAll();

use League\Csv\Writer;

//we fetch the info from a DB using a PDO object
$sth = $dbh->prepare(
    "SELECT firstname, lastname, email FROM users LIMIT 200"
);
//because we don't want to duplicate the data for each row
// PDO::FETCH_NUM could also have been used
$sth->setFetchMode(PDO::FETCH_ASSOC);
$sth->execute();

//we create the CSV into memory
$csv = Writer::createFromFileObject(new SplTempFileObject());

//we insert the CSV header
$csv->insertOne(['firstname', 'lastname', 'email']);

// The PDOStatement Object implements the Traversable Interface
// that's why Writer::insertAll can directly insert
// the data into the CSV
$csv->insertAll($sth);

// Because you are providing the filename you don't have to
// set the HTTP headers Writer::output can
// directly set them for you
// The file is downloadable
$csv->output('users.csv');
die;

use League\Csv\Reader;

//We are going to insert some data into the users table
$sth = $dbh->prepare(
    "INSERT INTO users (firstname, lastname, email) VALUES (:firstname, :lastname, :email)"
);

$csv = Reader::createFromPath('/path/to/your/csv/file.csv', 'r');
$csv->setOffset(1); //because we don't want to insert the header
$nbInsert = $csv->each(function ($row) use (&$sth) {
    //Do not forget to validate your data before inserting it in your database
    $sth->bindValue(':firstname', $row[0], PDO::PARAM_STR);
    $sth->bindValue(':lastname', $row[1], PDO::PARAM_STR);
    $sth->bindValue(':email', $row[2], PDO::PARAM_STR);

    return $sth->execute(); //if the function return false then the iteration will stop
});

use League\Csv\Reader;

$reader = Reader::createFromPath('/path/to/your/csv/file.csv', 'r');

$input_bom = $reader->getInputBOM();

if ($input_bom === Reader::BOM_UTF16_LE || $input_bom === Reader::BOM_UTF16_BE) {
    $reader->appendStreamFilter('convert.iconv.UTF-16/UTF-8');
}

foreach ($reader->fetchAssoc(0) as $row) {
    echo json_encode($row, JSON_PRETTY_PRINT), PHP_EOL;
}