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pythonmatplotlibviolin-plot

Changing the color of matplotlib's violin plots

Is there a way to change the color of the violin plots in matplotlib?

The default color is this "brownish" color, which is not too bad, but I'd like to color e.g., the first 3 violins differently to highlight them. I don't find any parameter in the documentation. Any ideas or hacks to color the violins differently?

enter image description here

Solution

  • matplotlib.pyplot.violinplot() says it returns:

    A dictionary mapping each component of the violinplot to a list of the corresponding collection instances created. The dictionary has the following keys:

    • bodies: A list of the matplotlib.collections.PolyCollection instances containing the filled area of each violin.
    • [...among others...]

    Methods of PolyCollections include:

    So, it looks like you could just loop through the result's body list and modify the facecolor of each:

    violin_parts = plt.violinplot(...)

for pc in violin_parts['bodies']:
    pc.set_facecolor('red')
    pc.set_edgecolor('black')

    It is a bit strange though that you can't set this when creating it like the common plot types. I'd guess it's probably because the operation creates so many bits (the aforementioned PolyCollection along with 5 other LineCollections), that additional arguments would be ambiguous.