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I'm trying to create a box & whisker plot of a set of data binning y versus x. I found an useful example in making binned boxplot in matplotlib with numpy and scipy in Python. The question is now very simple. How can I specify the color of the boxes in matplotlib.pyplot.boxplot as I would like to set it transparent in order to let the reader also to see the original data. I know there exists the example shown in http://matplotlib.sourceforge.net/examples/pylab_examples/boxplot_demo2.html but is anything simpler than this? It looks strange the impossibility to set the color of the boxes directly in boxplot Thank you in advance

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Nicola Vianello
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1 Answers1

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You could just render the original data as a scatter plot behind the boxplot and then hide the fliers of the boxplot. 

import pylab
import numpy

pylab.figure()

data = [numpy.random.normal(i, size=50) for i in xrange(5)]

for x, y in enumerate(data):
    pylab.scatter([x + 1 for i in xrange(50)], y, alpha=0.5, edgecolors='r', marker='+')

bp = pylab.boxplot(data)
pylab.setp(bp['boxes'], color='black')
pylab.setp(bp['whiskers'], color='black')
pylab.setp(bp['fliers'], marker='None')

pylab.xlim(0,6)

pylab.show()

enter image description here

Alexey Grigorev
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Henning
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  • Thank you for the response. I'm just wondering that in this way you set to 'black' the contour of the boxes. If you want them filled with patch_artist=True how can I set the color of the filling? – Nicola Vianello Jul 01 '11 at 11:05
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    I finally found the solution. I've to set the properties of the Patches created (using path_artist=True) in box plot like this pylab.setp(bp['boxes'],facecolor='cyan',alpha=0.5) – Nicola Vianello Jul 01 '11 at 12:27
  • Trying to recolour boxplots too.. I figured iterating through the mappings (returned by boxplot()) would be messy. Should have known about that setp() method - looks very handy! – Alex Leach Jul 02 '11 at 22:45
  • @Nicola Vianello Your proposal does not work on my system. It raises an AttributeError with message "'Line2D' object has no attribute 'set_facecolor'". It actually works on your system? Weird... – Christian O'Reilly Oct 03 '13 at 21:54
  • Nicola's comment worked for be, but I had to use, `patch_artist=True` instead of `path_artist=True` – klaus se Dec 10 '13 at 15:08