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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Customised dashed linstyle in matplotlib.cycler throws ValueError when using in Axes.set_prop_cycle","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\nUsing a cycler from matplotlib with a customised dashed linestyle for the property cycle in Axes.set_prop_cycle throws a ValueError (see below). Importing cycler from cycler works as expected.\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug.\r\nPlease make sure to minimize the number of dependencies required, and provide\r\nany necessary plotted data.\r\nAvoid using threads, as Matplotlib is (explicitly) not thread-safe.--\u003e\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nfrom matplotlib import rcParams\r\nfrom matplotlib import cycler # from cycler import cycler works fine\r\n\r\ncc = cycler('linestyle', [(0,(3,1)), '-'])\r\n\r\nfig = plt.figure()\r\nax = fig.add_subplot(221)\r\nax.set_prop_cycle(cc)\r\nax.plot(range(10))\r\n\r\n```\r\n\r\n**Actual outcome**\r\n\r\n\r\n```\r\nTraceback (most recent call last):\r\n  File \"err.py\", line 10, in \u003cmodule\u003e\r\n    ax.plot(range(10))\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/axes/_axes.py\", line 1665, in plot\r\n    lines = [*self._get_lines(*args, data=data, **kwargs)]\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/axes/_base.py\", line 225, in __call__\r\n    yield from self._plot_args(this, kwargs)\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/axes/_base.py\", line 405, in _plot_args\r\n    seg = func(x[:, j % ncx], y[:, j % ncy], kw, kwargs)\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/axes/_base.py\", line 312, in _makeline\r\n    seg = mlines.Line2D(x, y, **kw)\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/lines.py\", line 377, in __init__\r\n    self.set_linestyle(linestyle)\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/lines.py\", line 1186, in set_linestyle\r\n    cbook._check_in_list([*self._lineStyles, *ls_mapper_r], ls=ls)\r\n  File \"/usr/local/lib/python3.7/site-packages/matplotlib/cbook/__init__.py\", line 2170, in _check_in_list\r\n    .format(v, k, ', '.join(map(repr, values))))\r\nValueError: '(0, (3, 1))' is not a valid value for ls; supported values are '-', '--', '-.', ':', 'None', ' ', '', 'solid', 'dashed', 'dashdot', 'dotted'\r\n```\r\n\r\n**Expected outcome**\r\n\r\nI would expect matplotlib.cycler to work the same as cycler.cycler. However, in this case matplotlib.cycler throws a ValueError.\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  * Operating system: macOS Mojave 10.14.6\r\n  * Matplotlib version: 3.1.2\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): MacOSX\r\n  * Python version: 3.7.4\r\n  * Jupyter version (if applicable): --\r\n  * Other libraries: --\r\n\r\nmatplotlib installed via pip\r\n","author":{"url":"https://github.com/sdschmidt","@type":"Person","name":"sdschmidt"},"datePublished":"2019-12-03T22:29:15.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/15825/matplotlib/issues/15825"}