Create a grouped bar plot in Matplotlib

In this article, we will learn how to Create a grouped bar plot in Matplotlib. Let’s discuss some concepts :

• Matplotlib is a tremendous visualization library in Python for 2D plots of arrays. Matplotlib may be a multi-platform data visualization library built on NumPy arrays and designed to figure with the broader SciPy stack. It had been introduced by John Hunter within the year 2002.
• A bar plot or bar graph may be a graph that represents the category of knowledge with rectangular bars with lengths and heights that’s proportional to the values which they represent. The bar plots are often plotted horizontally or vertically.
• A bar chart is a great way to compare categorical data across one or two dimensions. More often than not, it’s more interesting to compare values across two dimensions and for that, a grouped bar chart is needed.

Approach:

1. Import Library (Matplotlib)
2. Import / create data.
3. Plot the bars in the grouped manner.

Example 1: (Simple grouped bar plot)

Python3

# importing package
import matplotlib.pyplot as plt
import numpy as np

# create data
x = np.arange(5)
y1 = [34, 56, 12, 89, 67]
y2 = [12, 56, 78, 45, 90]
width = 0.40

# plot data in grouped manner of bar type
plt.bar(x-0.2, y1, width)
plt.bar(x+0.2, y2, width)

Output :

Example 2: (Grouped bar chart with more than 2 data)

Python3

# importing package
import matplotlib.pyplot as plt
import numpy as np

# create data
x = np.arange(5)
y1 = [34, 56, 12, 89, 67]
y2 = [12, 56, 78, 45, 90]
y3 = [14, 23, 45, 25, 89]
width = 0.2

# plot data in grouped manner of bar type
plt.bar(x-0.2, y1, width, color='cyan')
plt.bar(x, y2, width, color='orange')
plt.bar(x+0.2, y3, width, color='green')
plt.xticks(x, ['Team A', 'Team B', 'Team C', 'Team D', 'Team E'])
plt.xlabel("Teams")
plt.ylabel("Scores")
plt.legend(["Round 1", "Round 2", "Round 3"])
plt.show()

Output :

Example 3: (Grouped Bar chart using dataframe plot)

Python3

# importing package
import matplotlib.pyplot as plt
import pandas as pd

# create data
df = pd.DataFrame([['A', 10, 20, 10, 30], ['B', 20, 25, 15, 25], ['C', 12, 15, 19, 6],
                   ['D', 10, 29, 13, 19]],
                  columns=['Team', 'Round 1', 'Round 2', 'Round 3', 'Round 4'])
# view data
print(df)

# plot grouped bar chart
df.plot(x='Team',
        kind='bar',
        stacked=False,
        title='Grouped Bar Graph with dataframe')

Output :