def _create_or_validate_filenames_dataset(filenames):
"""Creates (or validates) a dataset of filenames.
Args:
filenames: Either a list or dataset of filenames. If it is a list, it is
convert to a dataset. If it is a dataset, its type and shape is validated.
Returns:
A dataset of filenames.
"""
if isinstance(filenames, dataset_ops.DatasetV2):
if dataset_ops.get_legacy_output_types(filenames) != dtypes.string:
raise TypeError(
"`filenames` must be a `tf.data.Dataset` of `tf.string` elements."
)
if not dataset_ops.get_legacy_output_shapes(
filenames).is_compatible_with(tensor_shape.TensorShape([])):
raise TypeError(
"`filenames` must be a `tf.data.Dataset` of scalar `tf.string` "
"elements.")
else:
filenames = nest.map_structure(_normalise_fspath, filenames)
filenames = ops.convert_to_tensor(filenames, dtype_hint=dtypes.string)
if filenames.dtype != dtypes.string:
raise TypeError(
"`filenames` must be a `tf.Tensor` of dtype `tf.string` dtype."
" Got {}".format(filenames.dtype))
filenames = array_ops.reshape(filenames, [-1], name="flat_filenames")
filenames = dataset_ops.TensorSliceDataset(filenames, is_files=True)
return filenames
def _create_or_validate_filenames_dataset(filenames, name=None):
"""Creates (or validates) a dataset of filenames.
Args:
filenames: Either a list or dataset of filenames. If it is a list, it is
convert to a dataset. If it is a dataset, its type and shape is validated.
name: (Optional.) A name for the tf.data operation.
Returns:
A dataset of filenames.
"""
if isinstance(filenames, dataset_ops.DatasetV2):
element_type = dataset_ops.get_legacy_output_types(filenames)
if element_type != dtypes.string:
raise TypeError(
"The `filenames` argument must contain `tf.string` elements. Got a "
f"dataset of `{element_type!r}` elements.")
element_shape = dataset_ops.get_legacy_output_shapes(filenames)
if not element_shape.is_compatible_with(tensor_shape.TensorShape([])):
raise TypeError(
"The `filenames` argument must contain `tf.string` elements of shape "
"[] (i.e. scalars). Got a dataset of element shape "
f"{element_shape!r}.")
else:
filenames = nest.map_structure(_normalise_fspath, filenames)
filenames = ops.convert_to_tensor(filenames, dtype_hint=dtypes.string)
if filenames.dtype != dtypes.string:
raise TypeError(
"The `filenames` argument must contain `tf.string` elements. Got "
f"`{filenames.dtype!r}` elements.")
filenames = array_ops.reshape(filenames, [-1], name="flat_filenames")
filenames = dataset_ops.TensorSliceDataset(filenames,
is_files=True,
name=name)
return filenames
def from_tensor_slices(tensors):
"""Creates a `Dataset` whose elements are slices of the given tensors.
Args:
tensors: A nested structure of tensors, each having the same size in the
0th dimension.
Returns:
A `Dataset`.
"""
return Dataset(dataset_ops.TensorSliceDataset(tensors))