René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Nan values in scatter 3d plot show in black colour when alpha parameter is passed.","articleBody":"### Bug summary\n\nIn a `projection='3d'` axis, a scatter plot with the `c` argument to colour the points is showing black markers in the position of nan values if the `alpha` argument is passed. If the `alpha` argument is not present, the nan values are not displayed, as expected. If the `alpha` argument is present, even with `alpha = 1`, the markers are coloured black.\n\n### Code for reproduction\n\n```python\nn_x = 200\r\nn_y = 1\r\nn_z = 200\r\n\r\n_x = np.linspace(-10,10,n_x)\r\n_y = 0 \r\n_z = np.linspace(-10,10,n_z)\r\n\r\n_xx, _yy, _zz = np.meshgrid(_x, _y, _z, indexing='ij')\r\nc = np.array(np.arange(n_x*n_y*n_z, dtype = float).reshape(n_x,n_y,n_z))\r\nc[int(n_x/4):int(n_x/2),:,:] = np.nan\r\n\r\nfig = plt.figure(figsize=(12, 5))\r\nax0 = fig.add_subplot(121, projection='3d')\r\nax0.scatter(_xx, _yy, _zz, c = c, marker = 's')\r\nax0.set_title('`alpha` OFF')\r\nax1 = fig.add_subplot(122, projection='3d')\r\nax1.set_title('`alpha` ON')\r\nscat3d = ax1.scatter(_xx, _yy, _zz, c = c, \r\n                     marker = 's', alpha = 1)\r\n\r\nplt.show()\n```\n\n\n### Actual outcome\n\n![download](https://user-images.githubusercontent.com/20727577/224797657-4c1eec1e-5d35-44cf-82cf-a41b8422ebcb.png)\r\n\n\n### Expected outcome\n\n![download](https://user-images.githubusercontent.com/20727577/224797741-8359e21a-a675-4559-8483-77f82de608e2.png)\r\n\n\n### Additional information\n\n_No response_\n\n### Operating system\n\nUbuntu\n\n### Matplotlib Version\n\n3.7.0\n\n### Matplotlib Backend\n\nmodule://matplotlib_inline.backend_inline\n\n### Python version\n\nPython 3.10.9\n\n### Jupyter version\n\n6.5.2\n\n### Installation\n\nconda","author":{"url":"https://github.com/ricmperes","@type":"Person","name":"ricmperes"},"datePublished":"2023-03-13T18:38:06.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/25446/matplotlib/issues/25446"}