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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Improper handling of color in set_color when data contains NaN.","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\n\u003c!--A short 1-2 sentences that succinctly describes the bug--\u003e\r\n\r\nWhen a scatter plot is made with data that contains np.nan (NaN), and then a color array is given using `set_color`, the wrong colors get mapped to the data points.\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug, also minimizing the number of dependencies required--\u003e\r\n\r\n```python\r\nfrom matplotlib import pyplot\r\nfrom matplotlib.colors import Normalize\r\nfrom matplotlib import cm\r\nimport numpy as np\r\n\r\nx = np.linspace(0.0, 1.0, 50)\r\ny = np.linspace(0.0, 1.0, 50)\r\nnorm = Normalize(0.0, 1.0)\r\ncolormap = cm.ScalarMappable(norm, 'gnuplot')\r\ncolors = colormap.to_rgba(y)\r\n\r\n# Expected colors with when x and y do not contain any np.nan.\r\n# Success.\r\nplot = pyplot.scatter(x, y, color=colors)\r\npyplot.show()\r\n\r\n# Add some nan values.  \r\n# If the color array is given during the initial creation of the\r\n# scatter plot, then everything works as expected.\r\n# Success.\r\nx[10:40] = np.nan\r\nplot = pyplot.scatter(x, y, color=colors)\r\npyplot.show()\r\n\r\n# Again add some nan values.  \r\n# If the color array is given as a call to set_color\r\n# then the colors no longer match the data.\r\n# Failure.\r\nx[10:40] = np.nan\r\nplot = pyplot.scatter(x, y)\r\nplot.set_color(colors)\r\npyplot.show()\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**Top:** Expected colors with when x and y do not contain any np.nan.\r\n\r\n**Middle:** Add some nan values.  If the color array is given during the initial creation of the scatter plot, then everything works as expected.\r\n\r\n**Bottom:** Again add some nan values.   If the color array is given as a call to `set_color` then the colors no longer match the data.\r\n\r\n![screen shot 2017-11-30 at 15 19 02](https://user-images.githubusercontent.com/228288/33435285-0de016fa-d5e2-11e7-8e30-41970eba57d8.png)\r\n\r\n\r\n\r\n**Expected outcome**\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\nThe colors corresponding to the data points should be displayed, even when data points contain NaN and `set_color` is used.\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: OSX\r\n  * Matplotlib version: 2.0.2\r\n  * Matplotlib backend: module://ipykernel.pylab.backend_inline \u0026 MacOSX\r\n  * Python version: 3.6.3\r\n  * Jupyter Notebook version: 5.2.0\r\n  * Other libraries: None\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\n","author":{"url":"https://github.com/amicitas","@type":"Person","name":"amicitas"},"datePublished":"2017-11-30T14:30:04.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":9},"url":"https://github.com/9891/matplotlib/issues/9891"}