René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: PolyCollection `set_offsets` does not accept `[[], []]` like Line2D","articleBody":"### Bug summary\r\n\r\nThe return value of `plot` a `Line2D` lets you `set_data` as `[[], []]` this is nice because you can do both of\r\n```python\r\nline = plt.plot([],[])[0]\r\nline.set_data([[],[]])\r\n```\r\nallowing you to make a line disappear by setting it's data to empty. This comes up surprisingly often for me when using mpl-interactions to explore datasets\r\n\r\n\r\nHowever, `plt.scatter` does not have the same symmetry of behavior. You can do \r\n```python\r\nscatter = plt.scatter([[], [])\r\n```\r\n\r\nbut you cannot then do \r\n```python\r\nscatter.set_offsets([[],[]])\r\n```\r\n\r\n### Code for reproduction\r\n\r\n```python\r\n# works\r\nline = plt.plot([],[])[0]\r\n\r\n# works\r\nline.set_data([[],[]])\r\n\r\n# works\r\nscatter = plt.scatter([],[])\r\n\r\n# fails\r\nscatter.set_offsets([[],[]])\r\n```\r\n\r\n\r\n### Actual outcome\r\n```\r\n---------------------------------------------------------------------------\r\nIndexError                                Traceback (most recent call last)\r\nInput In [76], in \u003cmodule\u003e\r\n      1 scatter = plt.scatter([],[])\r\n----\u003e 2 scatter.set_offsets([[],[]])\r\n\r\nFile ~/mambaforge/envs/mpl-inter/lib/python3.9/site-packages/matplotlib/collections.py:566, in Collection.set_offsets(self, offsets)\r\n    563 if offsets.shape == (2,):  # Broadcast (2,) -\u003e (1, 2) but nothing else.\r\n    564     offsets = offsets[None, :]\r\n    565 self._offsets = np.column_stack(\r\n--\u003e 566     (np.asarray(self.convert_xunits(offsets[:, 0]), 'float'),\r\n    567      np.asarray(self.convert_yunits(offsets[:, 1]), 'float')))\r\n    568 self.stale = True\r\n\r\nIndexError: index 0 is out of bounds for axis 1 with size 0\r\n```\r\n### Expected outcome\r\n\r\nNo error and the scatter should not be drawn.\r\n\r\n### Additional information\r\n\r\n_No response_\r\n\r\n### Operating system\r\n\r\n_No response_\r\n\r\n### Matplotlib Version\r\n\r\n3.5.1\r\n\r\n### Matplotlib Backend\r\n\r\nany\r\n\r\n### Python version\r\n\r\n3.9.9\r\n\r\n### Jupyter version\r\n\r\n_No response_\r\n\r\n### Installation\r\n\r\npip","author":{"url":"https://github.com/ianhi","@type":"Person","name":"ianhi"},"datePublished":"2022-02-05T05:19:45.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/22401/matplotlib/issues/22401"}