Group Bar Chart with Seaborn/Matplotlib

Question

My goal is to create a grouped bar chart like the one below, using a pandas DataFrame that is grouped by two variables "Alpha" and "Beta."

xl2 = xl.groupby(['Alpha','Beta']).median()

When I tried this, a KeyError was thrown on 'Alpha'

import seaborn as sns
sns.barplot(x=['Alpha', 'Beta'], y=xl2['Gamma'])

My hope was to pass in a list of x values to index on ('Alpha' and 'Beta'), and graph the associated 'Gamma." The documentation for the seaborn.barplot function doesn't provide any group bar chart examples.

Thanks for your help!

Solution

You can use ggplot for this

from ggplot import *
import pandas as pd
import numpy as np

df = pd.DataFrame({
    "x": np.random.choice(range(2001, 2008), 250),
    "w": np.random.uniform(50, 400, 250),
    "cat": np.random.choice(["A", "B", "C", "D", "E"], 250)
})

print ggplot(df, aes(x='x', weight='w', fill='cat')) + geom_bar() + theme_bw()

Comments

[NumenorForLife]

Almost. The index is composed of two items. I want one item (Beta) to appear alongside the graph as a legend. Currently, the x-label is formatted in the following way ('Alpha', Beta)