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Matplotlib II

Bar Charts

Learn how to create vertical and horizontal bar charts using plt.bar() and plt.barh(), and how to customize their colors.

Bar charts are ideal for comparing values across categories. Use plt.bar() for vertical bars and plt.barh() for horizontal bars.

Let's create a simple vertical bar chart comparing language popularity:

import matplotlib.pyplot as plt
 
languages = [
    'Python', 'JavaScript',
    'Java', 'C++', 'Rust'
]
popularity = [30, 25, 18, 14, 8]
 
plt.bar(languages, popularity)
plt.title('Most Popular Languages')
plt.xlabel('Language')
plt.ylabel('Usage (%)')
plt.show()

Python

Output

The first argument to plt.bar() is the category labels, the second is the bar heights. Labels and title work just like in line plots.

What will be the output?

Python

 plt.bar()
 Output

 plt.barh()
 Output

 plt.plot()
 Output

Use the color parameter to set bar colors — pass a single color or a list of colors:

import matplotlib.pyplot as plt
 
languages = [
    'Python', 'JavaScript',
    'Java', 'C++', 'Rust'
]
popularity = [30, 25, 18, 14, 8]
colors = [
    '#4c72b0', '#dd8452',
    '#55a868', '#c44e52', '#8172b2'
]
 
plt.bar(languages, popularity, color=colors)
plt.title('Most Popular Languages')
plt.xlabel('Language')
plt.ylabel('Usage (%)')
plt.show()

Python

Output

What will be the output?

Python

 plt.bar(x, y, color='red')
 Output

 plt.bar(x, y, fill='red')
 Output

 plt.bar(x, y, style='red')
 Output

Horizontal bar charts work well when category labels are long. Use plt.barh() — the axes are swapped, so xlabel labels the value axis:

import matplotlib.pyplot as plt
 
languages = [
    'Python', 'JavaScript',
    'Java', 'C++', 'Rust'
]
popularity = [30, 25, 18, 14, 8]
 
plt.barh(languages, popularity,
         color='steelblue')
plt.title('Most Popular Languages')
plt.xlabel('Usage (%)')
plt.show()

Python

Output

What will be the output?

Python

 The x-axis
 Output

 The y-axis
 Output

 Both axes equally
 Output

What will be the output?

Python

 plt.bar() is vertical; plt.barh() is horizontal
 Output

 plt.bar() uses lists; plt.barh() uses arrays
 Output

 They are identical — just aliases
 Output

What will be the output?

Python

 Horizontal bar chart (plt.barh)
 Output

 Vertical bar chart (plt.bar)
 Output

 Line plot (plt.plot)
 Output

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