generateRandomAlphabeticString(3) . $this->generateRandomNumericString(3); } public function generateRandomAlphabeticString($length = 6) { $characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; $charactersLength = strlen($characters); $randomString = ''; for ($i = 0; $i < $length; $i++) { $randomString .= $characters[rand(0, $charactersLength - 1)]; } return $randomString; } public function generateRandomNumericString($length = 6) { $characters = '1234567890'; $charactersLength = strlen($characters); $randomString = ''; for ($i = 0; $i < $length; $i++) { $randomString .= $characters[rand(0, $charactersLength - 1)]; } return $randomString; } }