Function SplitV2

tensorflow/core/kernels/string_split_op.cc:128–184

}

std::vector<StringPiece> SplitV2(const string& str, StringPiece sep,
                                 int maxsplit) {
  // This SplitV2 method matches the behavior of python's str.split:
  //   If sep is given, consecutive delimiters are not grouped together
  //   and are deemed to delimit empty strings (for example, '1,,2'.split(',')
  //   returns ['1', '', '2']). The sep argument may consist of multiple
  //   characters (for example, '1<>2<>3'.split('<>') returns ['1', '2', '3']).
  //   Splitting an empty string with a specified separator returns [''].
  //
  //   If sep is not specified or is None, a different splitting algorithm is
  //   applied: runs of consecutive whitespace are regarded as a single
  //   separator, and the result will contain no empty strings at the start or
  //   end if the string has leading or trailing whitespace. Consequently,
  //   splitting an empty string or a string consisting of just whitespace
  //   with a None separator returns [].

  std::vector<StringPiece> result;

  StringPiece text(str);
  if (maxsplit == 0) {
    result.emplace_back(text);
    return result;
  }

  if (sep.empty()) {
    StringPiece token;
    // Remove leading whitespaces.
    str_util::RemoveLeadingWhitespace(&text);
    int split = 0;
    while (str_util::ConsumeNonWhitespace(&text, &token)) {
      result.push_back(token);
      str_util::RemoveLeadingWhitespace(&text);
      ++split;
      if (maxsplit > 0 && split == maxsplit) {
        result.push_back(text);
        return result;
      }
    }
    return result;
  }
  auto p = std::search(text.begin(), text.end(), sep.begin(), sep.end());
  int split = 0;
  while (p != text.end()) {
    StringPiece token = text.substr(0, p - text.begin());
    result.push_back(token);
    text.remove_prefix(token.size());
    text.remove_prefix(sep.size());
    ++split;
    if (maxsplit > 0 && split == maxsplit) {
      result.push_back(StringPiece(text));
      return result;
    }
    p = std::search(text.begin(), text.end(), sep.begin(), sep.end());
  }
  result.push_back(text);
  return result;
}