bug

Hi Yan,

in the Graph Gallery in some example in Python there are mistakes
for example in the "Show Number of Observations"

import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns
import pandas as pd

Dataset:

a = pd.DataFrame({ 'group' : np.repeat('A',500), 'value': np.random.normal(10, 5, 500) })
b = pd.DataFrame({ 'group' : np.repeat('B',500), 'value': np.random.normal(13, 1.2, 500) })
c = pd.DataFrame({ 'group' : np.repeat('B',500), 'value': np.random.normal(18, 1.2, 500) })
d = pd.DataFrame({ 'group' : np.repeat('C',20), 'value': np.random.normal(25, 4, 20) })
e = pd.DataFrame({ 'group' : np.repeat('D',100), 'value': np.random.uniform(12, size=100) })
df = pd.concat([a,b,c,d,e])

Start with a basic boxplot

sns.boxplot(x="group", y="value", data=df) # the assignment ax is missing

Calculate number of obs per group & median to position labels

medians = df.groupby(['group'])['value'].median().values
nobs = df.groupby("group").size().values
nobs = [str(x) for x in nobs.tolist()]
nobs = ["n: " + i for i in nobs]

Add it to the plot

pos = range(len(nobs))
for tick,label in zip(pos,ax.get_xticklabels()):
plt.text(pos[tick], medians[tick] + 0.4, nobs[tick], horizontalalignment='center', size='medium', color='w', weight='semibold')

add title

plt.title("Boxplot with number of observation", loc="left")

show the graph

plt.show()

================

Best regards

--Marco

The issue points to the Graph Gallery's “Show Number of Observations” Python example; start by checking the boxplot setup and the later ax.get_xticklabels() use. Confirm the example runs and renders the observation-count labels, then inspect other Python examples for the same reported mistake.