dataset_schema.py 文件源码

def _from_parse_feature(parse_feature):
  """Convert a single feature spec to a ColumnSchema."""

  # FixedLenFeature
  if isinstance(parse_feature, tf.FixedLenFeature):
    representation = FixedColumnRepresentation(parse_feature.default_value)
    return ColumnSchema(parse_feature.dtype, parse_feature.shape,
                        representation)

  # FixedLenSequenceFeature
  if isinstance(parse_feature, tf.FixedLenSequenceFeature):
    raise ValueError('DatasetSchema does not support '
                     'FixedLenSequenceFeature yet.')

  # VarLenFeature
  if isinstance(parse_feature, tf.VarLenFeature):
    representation = ListColumnRepresentation()
    return ColumnSchema(parse_feature.dtype, [None], representation)

  # SparseFeature
  if isinstance(parse_feature, tf.SparseFeature):
    index_field = SparseIndexField(name=parse_feature.index_key,
                                   is_sorted=parse_feature.already_sorted)
    representation = SparseColumnRepresentation(
        value_field_name=parse_feature.value_key,
        index_fields=[index_field])
    return ColumnSchema(parse_feature.dtype, [parse_feature.size],
                        representation)

  raise ValueError('Cannot interpret feature spec {} with type {}'.format(
      parse_feature, type(parse_feature)))