Function IsDigitStr

src/common/util/string_util.h:495–501

* @brief determines whether the string is composed of numbers * * @param[in] str string to be judged * @return true All are composed of numbers * @return false Not all composed of numbers */

 * @return false Not all composed of numbers
 */
inline bool IsDigitStr(std::string_view str) {
  if (str.length() == 0) return false;
  for (const auto& c : str) {
    if (c > '9' || c < '0') return false;
  }
  return true;
}

/**
 * @brief Get the collection of keys in map