“Can't broadcast (37,) -> (37, 2)” while writing in a H5 file

Question

I want to insert in a raw of my H5 file an array containing (x, y) coordinates and None values where the coordinates are (0.0, 0.0) :

This is my code:

none_matrix = np.zeros((num_images, len(skeleton_names_list), 2))
for i in range(num_images):
    for j in range(len(skeleton_names_list)):
        none_matrix[i][j] = None

hf.create_dataset('annotations', shape=(num_images, len(skeleton_names_list), 2), dtype=np.float64, data=none_matrix)
# hf.create_dataset('annotated', shape=(num_images, len(skeleton_names_list)), dtype=bool)

joints_coordinates = []
num_ann = 0
j_file = open('dog.json')
j_data = json.load(j_file)
for xy in j_data:
    joints_coordinates.append(xy['joints'])
    image_name = xy['segmentation_path']
    image_index = idx_dict.get(image_name)
    for i in range(len(skeleton_names_list)):
        if joints_coordinates[num_ann][i][0] + joints_coordinates[num_ann][i][1] == 0:
            joints_coordinates[num_ann][i] = None
    hf["annotations"][image_index] = joints_coordinates[num_ann]
    # hf["annotated"][image_index] = np.ones(len(skeleton_names_list), int)
    num_ann += 1

Why do I get this error?

    Traceback (most recent call last):
      File "C:/Users/Alberto Ursino/Desktop/IntellIj Local Files/Write on H5/write.py", line 120, in <module>
        hf["annotations"][image_index] = joints_coordinates[num_ann]
      File "h5py\_objects.pyx", line 54, in h5py._objects.with_phil.wrapper
      File "h5py\_objects.pyx", line 55, in h5py._objects.with_phil.wrapper
      File "C:\Users\Alberto Ursino\anaconda3\envs\TensorFlow 1x\lib\site-packages\h5py\_hl\dataset.py", line 707, in __setitem__
        for fspace in selection.broadcast(mshape):
      File "C:\Users\Alberto Ursino\anaconda3\envs\TensorFlow 1x\lib\site-packages\h5py\_hl\selections.py", line 299, in broadcast
        raise TypeError("Can't broadcast %s -> %s" % (target_shape, self.mshape))
    TypeError: Can't broadcast (37,) -> (37, 2)

joints_coordinates is in the form:

[[[x, y], ...], ...]

Answer 1

Writing np.nan instead of None here:

for i in range(len(skeleton_names_list)):
        if joints_coordinates[num_ann][i][0] + joints_coordinates[num_ann][i][1] == 0:
            joints_coordinates[num_ann][i] = None

works!