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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"SecondaryAxis.grid() fails silently","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\nThis code is copy-pasted from [this SO question](https://stackoverflow.com/questions/64784834/draw-grid-line-on-secondaryaxis-matplotlib).\r\n\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\n\u003c!--A short 1-2 sentences that succinctly describes the bug--\u003e\r\n\r\nCreating a secondary axis and calling the `.grid()` method on it does not draw a grid. If it should not draw grid, it should throw an Exception. \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\nimport numpy as np\r\n\r\n\r\ndef get_data_and_ticks():\r\n\r\n    # generate dummy load duration curve\r\n    dur = 2500\r\n    y = np.random.normal(60, 30, dur + 1)\r\n    y[::-1].sort()\r\n\r\n    x = range(0, dur + 1)\r\n    perticks = np.linspace(0, 1, 11)\r\n    xticks = perticks * dur\r\n    yticks = np.interp(xticks, range(0, dur + 1), y)\r\n\r\n    return x, y, xticks, yticks\r\n\r\n\r\nx, y, xticks, yticks = get_data_and_ticks()\r\n\r\n# create figure object with axe object\r\nfig, ax1 = plt.subplots(figsize=(10, 7))\r\nax1.plot(x, y)\r\n\r\n# create second axis\r\ncolor = \"tab:blue\"\r\n\r\nax2 = ax1.secondary_yaxis(\"right\")\r\nax2.set_yticks(yticks)\r\nax2.set_yticklabels(labels=[f\"{i*10}%\" for i in range(11)])\r\nax2.tick_params(axis=\"y\", color=color, labelcolor=color)\r\n\r\n# draw grid lines on the secondaryaxis\r\n# The problem is at this line\r\nax2.grid(color=color, which=\"major\", linestyle=\"--\")\r\n\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n![image](https://user-images.githubusercontent.com/17479683/98970013-23808480-2518-11eb-8758-5e5c9748bd86.png)\r\n\r\n\r\n**Expected outcome**\r\n\r\n**Alternative A**\r\ndraw a figure like this:\r\n\r\n![image](https://user-images.githubusercontent.com/17479683/98970115-3f842600-2518-11eb-8517-4634928705cf.png)\r\n\r\n**Alternative B**\r\nRaise an exception and tell the user that `SecondaryAxis.grid()` is not supported.\r\n\r\n\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  * Operating system: Windows 10\r\n  * Matplotlib version:  3.3.3\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): TkAgg\r\n  * Python version: 3.8.6 64-bit\r\n\r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\n\r\nSame applies if a SecondaryAxis is created for `x` (`ax1.secondary_xaxis(\"top\")`)","author":{"url":"https://github.com/fohrloop","@type":"Person","name":"fohrloop"},"datePublished":"2020-11-12T16:56:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/18941/matplotlib/issues/18941"}