pandas - boxplot median color settings issues

Question

I'm running Pandas 0.16.2 and Matplotlib 1.4.3. I have this issue coloring the median of the boxplot generated by the following code:

df = pd.DataFrame(np.random.rand(10, 5), columns=['A', 'B', 'C', 'D', 'E'])

fig, ax = plt.subplots()

medianprops = dict(linestyle='-', linewidth=2, color='blue')

bp = df.boxplot(medianprops=medianprops)

plt.show()

That returns:

It appears that the color setting is not read. Changing only the settings of linestyle and linewidth the plot reacts correctly.

medianprops = dict(linestyle='-.', linewidth=5, color='blue')

Anyone can reproduce it?

Answer 1

Looking at the code for DataFrame.boxplot() there is some special code to handle the colors of the different elements that supersedes the kws passed to matplotlib's boxplot. In theory, there seem to be a way to pass a color= argument containing a dictionary with keys being 'boxes', 'whiskers', 'medians', 'caps' but I can't seem to get it to work when calling boxplot() directly.

However, this seem to work:

df.plot(kind='box', color={'medians': 'blue'}, 
        medianprops={'linestyle': '--', 'linewidth': 5})

see Pandas Boxplot Examples