这是将Keras ImageDataGenerator与.flow_from_directory一起使用，并用tf.data.Dataset.from_generator（...）包装的情况。数据集尝试对其进行任何迭代均失败。
错误摘要：
[InvalidArgumentError：TypeError：结尾于第一个arg必须是字节或字节元组，而不是str
代码段：
import tensorflow as tf # version 2.1.0
DATA_URL = 'https://storage.googleapis.com/download.tensorflow.org/example_images/flower_photos.tgz'
flowers_root_path = tf.keras.utils.get_file(origin=DATA_URL, fname='flower_photos', untar=True)
img_gen = tf.keras.preprocessing.image.ImageDataGenerator(rescale=1./255, rotation_range=20)
gen = img_gen.flow_from_directory(flowers_root_path)
ds = tf.data.Dataset.from_generator(
# lambda: gen, # this works
img_gen.flow_from_directory, args=[flowers_root_path], # this failed.
output_types=(tf.float32, tf.float32),
output_shapes=([32,256,256,3], [32,5])
)
it = iter(ds)
batch = next(it)
print(batch)
使用“ lambda：gen”看起来还不错。知道为什么吗？
完整堆栈跟踪：
---------------------------------------------------------------------------
InvalidArgumentError Traceback (most recent call last)
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/eager/context.py in execution_mode(mode)
1896 ctx.executor = executor_new
-> 1897 yield
1898 finally:
10 frames
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/iterator_ops.py in _next_internal(self)
658 output_types=self._flat_output_types,
--> 659 output_shapes=self._flat_output_shapes)
660
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/ops/gen_dataset_ops.py in iterator_get_next_sync(iterator, output_types, output_shapes, name)
2478 except _core._NotOkStatusException as e:
-> 2479 _ops.raise_from_not_ok_status(e, name)
2480 # Add nodes to the TensorFlow graph.
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/framework/ops.py in raise_from_not_ok_status(e, name)
6605 # pylint: disable=protected-access
-> 6606 six.raise_from(core._status_to_exception(e.code, message), None)
6607 # pylint: enable=protected-access
/usr/local/lib/python3.6/dist-packages/six.py in raise_from(value, from_value)
InvalidArgumentError: TypeError: endswith first arg must be bytes or a tuple of bytes, not str
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 673, in get_iterator
return self._iterators[iterator_id]
KeyError: 0
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/ops/script_ops.py", line 236, in __call__
ret = func(*args)
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 789, in generator_py_func
values = next(generator_state.get_iterator(iterator_id))
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 675, in get_iterator
iterator = iter(self._generator(*self._args.pop(iterator_id)))
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/image_data_generator.py", line 540, in flow_from_directory
interpolation=interpolation
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/directory_iterator.py", line 126, in __init__
classes, filenames = res.get()
File "/usr/lib/python3.6/multiprocessing/pool.py", line 644, in get
raise self._value
File "/usr/lib/python3.6/multiprocessing/pool.py", line 119, in worker
result = (True, func(*args, **kwds))
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/utils.py", line 216, in _list_valid_filenames_in_directory
for root, fname in valid_files:
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/utils.py", line 172, in _iter_valid_files
if fname.lower().endswith('.tiff'):
TypeError: endswith first arg must be bytes or a tuple of bytes, not str
[[{{node PyFunc}}]] [Op:IteratorGetNextSync]
During handling of the above exception, another exception occurred:
InvalidArgumentError Traceback (most recent call last)
<ipython-input-56-a2623f5ab104> in <module>()
1 it = iter(ds)
----> 2 batch = next(it)
3 print(batch)
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/iterator_ops.py in __next__(self)
628
629 def __next__(self): # For Python 3 compatibility
--> 630 return self.next()
631
632 def _next_internal(self):
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/iterator_ops.py in next(self)
672 """Returns a nested structure of `Tensor`s containing the next element."""
673 try:
--> 674 return self._next_internal()
675 except errors.OutOfRangeError:
676 raise StopIteration
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/iterator_ops.py in _next_internal(self)
663 return self._element_spec._from_compatible_tensor_list(ret) # pylint: disable=protected-access
664 except AttributeError:
--> 665 return structure.from_compatible_tensor_list(self._element_spec, ret)
666
667 @property
/usr/lib/python3.6/contextlib.py in __exit__(self, type, value, traceback)
97 value = type()
98 try:
---> 99 self.gen.throw(type, value, traceback)
100 except StopIteration as exc:
101 # Suppress StopIteration *unless* it's the same exception that
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/eager/context.py in execution_mode(mode)
1898 finally:
1899 ctx.executor = executor_old
-> 1900 executor_new.wait()
1901
1902
/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/eager/executor.py in wait(self)
65 def wait(self):
66 """Waits for ops dispatched in this executor to finish."""
---> 67 pywrap_tensorflow.TFE_ExecutorWaitForAllPendingNodes(self._handle)
68
69 def clear_error(self):
InvalidArgumentError: TypeError: endswith first arg must be bytes or a tuple of bytes, not str
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 673, in get_iterator
return self._iterators[iterator_id]
KeyError: 0
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/ops/script_ops.py", line 236, in __call__
ret = func(*args)
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 789, in generator_py_func
values = next(generator_state.get_iterator(iterator_id))
File "/usr/local/lib/python3.6/dist-packages/tensorflow_core/python/data/ops/dataset_ops.py", line 675, in get_iterator
iterator = iter(self._generator(*self._args.pop(iterator_id)))
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/image_data_generator.py", line 540, in flow_from_directory
interpolation=interpolation
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/directory_iterator.py", line 126, in __init__
classes, filenames = res.get()
File "/usr/lib/python3.6/multiprocessing/pool.py", line 644, in get
raise self._value
File "/usr/lib/python3.6/multiprocessing/pool.py", line 119, in worker
result = (True, func(*args, **kwds))
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/utils.py", line 216, in _list_valid_filenames_in_directory
for root, fname in valid_files:
File "/usr/local/lib/python3.6/dist-packages/keras_preprocessing/image/utils.py", line 172, in _iter_valid_files
if fname.lower().endswith('.tiff'):
TypeError: endswith first arg must be bytes or a tuple of bytes, not str
[[{{node PyFunc}}]]
根据此Stack Overflow Answer，您可以通过替换]使代码正常运行>
gen = img_gen.flow_from_directory(flowers_root_path)与
def Gen(): gen = img_gen.flow_from_directory(flowers_root_path) for (x,y) in gen: yield (x,y)完整的工作代码如下所示：
import tensorflow as tf # version 2.1.0 DATA_URL = 'https://storage.googleapis.com/download.tensorflow.org/example_images/flower_photos.tgz' flowers_root_path = tf.keras.utils.get_file(origin=DATA_URL, fname='flower_photos', untar=True) img_gen = tf.keras.preprocessing.image.ImageDataGenerator(rescale=1./255, rotation_range=20) def Gen(): gen = img_gen.flow_from_directory(flowers_root_path) for (x,y) in gen: yield (x,y) ds = tf.data.Dataset.from_generator( Gen, output_types=(tf.float32, tf.float32), output_shapes=([32,256,256,3], [32,5])) it = iter(ds) batch = next(it) print(batch)也请找到带有工作代码的Github Gist。