Diverging bar charts in Matplotlib

Introduction

Diverging bar charts help us compare positive and negative values side by side. They make it easy to see which items are above or below a baseline.

Comparing survey results with positive and negative responses.

Showing profit and loss for different products.

Visualizing changes that go up or down from zero.

Highlighting differences in ratings above or below average.

Syntax

Matplotlib

import matplotlib.pyplot as plt

# Data
labels = ['A', 'B', 'C', 'D']
values = [10, -5, 15, -10]

# Plot
plt.bar(labels, values, color=['green' if v >= 0 else 'red' for v in values])
plt.axhline(0, color='black')
plt.show()

Use colors to separate positive and negative bars for clarity.

Draw a horizontal line at zero to show the baseline.

Examples

Simple diverging bar chart with custom colors for positive and negative values.

Matplotlib

import matplotlib.pyplot as plt

labels = ['Jan', 'Feb', 'Mar']
values = [20, -10, 15]

colors = ['blue' if v >= 0 else 'orange' for v in values]
plt.bar(labels, values, color=colors)
plt.axhline(0, color='gray')
plt.show()

Adding a title to the diverging bar chart for better understanding.

Matplotlib

import matplotlib.pyplot as plt

labels = ['X', 'Y', 'Z']
values = [-5, 10, -3]

plt.bar(labels, values, color=['red' if v < 0 else 'green' for v in values])
plt.axhline(0, color='black')
plt.title('Diverging Bar Chart')
plt.show()

Sample Program

This program creates a diverging bar chart showing positive and negative values for products. Green bars go up, red bars go down, and a black line marks zero.

Matplotlib

import matplotlib.pyplot as plt

# Categories and their values
categories = ['Product A', 'Product B', 'Product C', 'Product D']
values = [30, -20, 15, -10]

# Choose colors: green for positive, red for negative
colors = ['green' if v >= 0 else 'red' for v in values]

# Create bar chart
plt.bar(categories, values, color=colors)

# Draw baseline at zero
plt.axhline(0, color='black')

# Add labels and title
plt.ylabel('Value')
plt.title('Diverging Bar Chart Example')

# Show plot
plt.show()

Important Notes

Always include a zero baseline line to separate positive and negative bars clearly.

Use contrasting colors for positive and negative bars to make the chart easy to read.

Keep labels short and clear to avoid clutter.

Summary

Diverging bar charts show positive and negative values side by side.

Use colors and a zero line to make differences clear.

They are great for comparing gains and losses or opinions above and below a midpoint.