numpy ma masked_equal returns ValueError: setting an array element with a sequence. when fill_value is float and missing_value is np.ndarray: setting anything but 0-dim array to scalar not allowed anymore in 2.4.0 #30591
Description
Describe the issue:
Hi folks, not sure if a bug - at any rate, a rather peculiar case: given a masked array, that has a fill_value, numpy ma.masked_equal fails when passing an ndarray (single element) for missing_value, works fine if float; this is new behaviour for numpy 2.4.0. Cheers very much! 🍺
Reproduce the code example:
import numpy as np
# works fine
missing_value = 33.
data = np.ma.array(
[[[-900., 33.], [33., -900], [33., 44.]]],
mask=False,
fill_value=-900.0,
dtype=float
)
s = np.ma.masked_equal(data, missing_value)
print(s)
# fails only with numpy=2.4.0
missing_value = np.array([33.], dtype=float)
data = np.ma.array(
[[[-900., 33.], [33., -900], [33., 44.]]],
mask=False,
fill_value=-900.0,
dtype=float
)
s = np.ma.masked_equal(data, missing_value)
print(s)Error message:
TypeError: only 0-dimensional arrays can be converted to Python scalars
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/valeriu/numpy_mre.py", line 23, in <module>
s = np.ma.masked_equal(data, missing_value)
File "/home/valeriu/miniconda3/envs/pyactive5/lib/python3.14/site-packages/numpy/ma/core.py", line 2161, in masked_equal
output.fill_value = value
^^^^^^^^^^^^^^^^^
File "/home/valeriu/miniconda3/envs/pyactive5/lib/python3.14/site-packages/numpy/ma/core.py", line 3850, in fill_value
_fill_value[()] = target
~~~~~~~~~~~^^^^
ValueError: setting an array element with a sequence.Python and NumPy Versions:
Python 3.14 and numpy 2.4.0
Runtime Environment:
No response
How does this issue affect you or how did you find it:
All fine, we fixed it so we use only floats for missing_value but others may be affected.