如何标记按熊猫分组的箱线图？

Question

I have a dataframe that I want to boxplot using groupby, The x-axis is labeled but the y-axis is not. How do I label the y-axis?

import pandas as pd, numpy as np

df = pd.DataFrame(np.random.rand(12,2), columns=['Apples', 'Oranges'] )
df['Categories'] = pd.Series(list('AAAABBBBCCCC'))
df.boxplot(by='Categories')
plt.ylabel("LABELLL")

I'd like the label 'LABELL' to be part of the plot, on the y axis. How do I do that?

Answer 1

ax = df.boxplot(by='Categories')
ax[0].set_ylabel("LABELLL")

df.boxplot returns a numpy.ndarray of matplotlib.axes.Axes objects. You can then set the ylabel on the first one.