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[Bug]: ValueError: The truth value... when an ndarray is passed to the color kwarg of axes3d.scatter #26821
Description
Bug summary
Passing a numpy array to the color argument of ax.scatter results in a ValueError when ax is initialized with projection='3d'. This error began occurring in our CI after the release of matplotlib 3.8.0.
Code for reproduction
import matplotlib.pyplot as plt
import numpy as np
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.scatter(1, 0, 0, color=np.array([0, 0, 0, 1]))
plt.show()Actual outcome
Traceback from our CI suite:
File "/home/runner/sct_6.1.dev0/testing/cli/test_cli_sct_dmri_display_bvecs.py", line 17, in test_sct_dmri_display_bvecs_png_exists
sct_dmri_display_bvecs.main(argv=['-bvec', sct_test_path('dmri', 'bvecs.txt')])
File "/home/runner/sct_6.1.dev0/spinalcordtoolbox/scripts/sct_dmri_display_bvecs.py", line 176, in main
ax.scatter(x[i], y[i], z[i], color=shell_colors[bvals[i]], alpha=0.7)
File "/home/runner/sct_6.1.dev0/python/envs/venv_sct/lib/python3.9/site-packages/matplotlib/__init__.py", line 1465, in inner
return func(ax, *map(sanitize_sequence, args), **kwargs)
File "/home/runner/sct_6.1.dev0/python/envs/venv_sct/lib/python3.9/site-packages/mpl_toolkits/mplot3d/axes3d.py", line 2377, in scatter
if kwargs.get('color', None):
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()Expected outcome
No error.
Additional information
NB: This is legacy code I'm maintaining but haven't actually written myself -- I only began looking at it after our CI threw an error after the upgrade from matplotlib 3.7.3 to 3.8.0.
- If I remove
projection='3d', the code does not error out. - If I pass a list (
[0, 0, 0, 1]) rather than an ndarray, the code does not error out, and displays a black, opaque point:
Operating system
Ubuntu 22.04
Matplotlib Version
3.8.0
Matplotlib Backend
module://backend_interagg
Python version
3.9.17, 3.10.12
Jupyter version
N/A
Installation
pip
Activity
ksunden commentedon Sep 18, 2023
This behavior was changed in #26249
I think that the conditional should actually be:
as it is using
.getreally only to determine if it is present or not.timhoffm commentedon Sep 19, 2023
I think the condition actually should be
To make explicit color=None work and comply with
from https://matplotlib.org/devdocs/api/_as_gen/matplotlib.axes.Axes.scatter.html#matplotlib.axes.Axes.scatter
github-actions commentedon Sep 19, 2023
Good first issue - notes for new contributors
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