René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Plot with dates cannot follow axhline","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nA call to `axhline` followed by plotting with dates yields an exception.\r\n\r\nThis arises when trying to reproduce #7742.\r\n\r\n**Code for reproduction**\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nfrom datetime import datetime\r\n\r\nfig, ax = plt.subplots()\r\n\r\nax.axhline(1.5)\r\nax.plot([datetime(2016, 1, 1, 0, 0, 0), datetime(2016, 1, 2, 0, 0, 0)], [1, 2])\r\n\r\n```\r\n\r\n**Actual outcome**\r\n\r\n\u003c!--The output produced by the above code, which may be a screenshot, console output, etc.--\u003e\r\n\r\n```\r\nTypeError                                 Traceback (most recent call last)\r\n\u003cipython-input-5-02e4fc5c74c6\u003e in \u003cmodule\u003e\r\n      5\r\n      6 ax.axhline(1.5)\r\n----\u003e 7 ax.plot([datetime(2016, 1, 1, 0, 0, 0), datetime(2016, 1, 2, 0, 0, 0)], [1, 2])\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/axes/_axes.py in plot(self, scalex, scaley, data, *args, **kwargs)\r\n   1743         lines = [*self._get_lines(*args, data=data, **kwargs)]\r\n   1744         for line in lines:\r\n-\u003e 1745             self.add_line(line)\r\n   1746         self._request_autoscale_view(scalex=scalex, scaley=scaley)\r\n   1747         return lines\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/axes/_base.py in add_line(self, line)\r\n   1975             line.set_clip_path(self.patch)\r\n   1976\r\n-\u003e 1977         self._update_line_limits(line)\r\n   1978         if not line.get_label():\r\n   1979             line.set_label('_line%d' % len(self.lines))\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/axes/_base.py in _update_line_limits(self, line)\r\n   1997         Figures out the data limit of the given line, updating self.dataLim.\r\n   1998         \"\"\"\r\n-\u003e 1999         path = line.get_path()\r\n   2000         if path.vertices.size == 0:\r\n   2001             return\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/lines.py in get_path(self)\r\n   1009         \"\"\"\r\n   1010         if self._invalidy or self._invalidx:\r\n-\u003e 1011             self.recache()\r\n   1012         return self._path\r\n   1013\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/lines.py in recache(self, always)\r\n    651         if always or self._invalidx:\r\n    652             xconv = self.convert_xunits(self._xorig)\r\n--\u003e 653             x = _to_unmasked_float_array(xconv).ravel()\r\n    654         else:\r\n    655             x = self._x\r\n\r\n~/work/programs/py/mpl/matplotlib/lib/matplotlib/cbook/__init__.py in _to_unmasked_float_array(x)\r\n   1296         return np.ma.asarray(x, float).filled(np.nan)\r\n   1297     else:\r\n-\u003e 1298         return np.asarray(x, float)\r\n   1299\r\n   1300\r\n~/miniconda3/envs/mpl1/lib/python3.7/site-packages/numpy/core/_asarray.py in asarray(a, dtype, order)\r\n     83\r\n     84     \"\"\"\r\n---\u003e 85     return array(a, dtype, copy=False, order=order)\r\n     86\r\n     87\r\n\r\nTypeError: float() argument must be a string or a number, not 'datetime.datetime'\r\n\r\n```\r\n\r\n**Expected outcome**\r\nA plot, with or without the bug from #7742.\r\n\u003c!--A description of the expected outcome from the code snippet--\u003e\r\n\u003c!--If this used to work in an earlier version of Matplotlib, please note the version it used to work on--\u003e\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n\r\n  * Matplotlib version: 3.3.0rc1.post273+gb803891a4b\r\n","author":{"url":"https://github.com/efiring","@type":"Person","name":"efiring"},"datePublished":"2020-07-14T23:55:23.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/17925/matplotlib/issues/17925"}