has($key) ? CsvUtils::toString($this[$key]) : $default; } public function getList($key, $default = []) { return $this->has($key) ? CsvUtils::toList($this[$key]) : $default; } public function has($key) { return isset($this[$key]); } public function keys() { return array_keys($this->getArrayCopy()); } public function set($key, $value = '') { $this->offsetSet($key, $value); return $this; } public function append($key, $value = '') { $data = $this->offsetGet($key); if (is_array($data)) { $this->offsetSet($key, array_merge($data, $value)); } elseif (is_scalar($data)) { $this->offsetSet($key, $data . $value); } return $this; } }