Encode a tf.Scalar string to a tf.Tensor.

    This will be necessary for on-the-fly tokenization.

    Args:
      s: a tf.Scalar with dtype tf.string
    Returns:
      a 1d tf.Tensor with dtype tf.int32

def encode_tf(self, s):
    """Encode a tf.Scalar string to a tf.Tensor.

    This will be necessary for on-the-fly tokenization.

    Args:
      s: a tf.Scalar with dtype tf.string
    Returns:
      a 1d tf.Tensor with dtype tf.int32
    """
    ids = subword_text_encoder_ops.subword_text_encoder_encode(
        s, self._filepath)
    # the c++ op apppends 1=EOS - drop it.
    return ids[:-1]