Heatmap with plt.pcolormesh in Matplotlib - Mini Project: Build & Apply

Heatmap with plt.pcolormesh

📖 Scenario: You work as a data analyst and want to visualize temperature data collected over a week in different cities. A heatmap is a great way to see patterns and differences quickly.

🎯 Goal: Create a heatmap using plt.pcolormesh to visualize the temperature data for 3 cities over 7 days.

📋 What You'll Learn

Create a 2D list called temperatures with exact temperature values for 3 cities over 7 days

Create a list called days with day names from Monday to Sunday

Create a list called cities with 3 city names

Use plt.pcolormesh to plot the heatmap with correct axis labels

Add a color bar to show the temperature scale

Print the heatmap plot

💡 Why This Matters

🌍 Real World

Heatmaps are used in weather forecasting, sales analysis, and many fields to quickly spot patterns in data.

💼 Career

Data analysts and scientists use heatmaps to visualize complex data simply and communicate insights effectively.

1

Create the temperature data

Create a 2D list called temperatures with these exact values: [[22, 21, 23, 24, 25, 26, 27], [18, 19, 20, 21, 22, 23, 24], [30, 29, 28, 27, 26, 25, 24]] representing temperatures for 3 cities over 7 days.

Matplotlib

# Your code here

Need a hint?

Use a list of lists to represent rows (cities) and columns (days).

2

Create the days and cities labels

Create a list called days with these exact values: ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']. Also create a list called cities with these exact values: ['CityA', 'CityB', 'CityC'].

Matplotlib

temperatures = [[22, 21, 23, 24, 25, 26, 27], [18, 19, 20, 21, 22, 23, 24], [30, 29, 28, 27, 26, 25, 24]]
# Your code here

Need a hint?

Use simple lists with the exact names and values.

3

Plot the heatmap using plt.pcolormesh

Import matplotlib.pyplot as plt. Use plt.pcolormesh to plot the heatmap of temperatures. Set the x-axis ticks to days and y-axis ticks to cities. Use plt.colorbar() to add a color bar.

Matplotlib

temperatures = [[22, 21, 23, 24, 25, 26, 27], [18, 19, 20, 21, 22, 23, 24], [30, 29, 28, 27, 26, 25, 24]]
days = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
cities = ['CityA', 'CityB', 'CityC']
# Your code here

Need a hint?

Use shading='auto' in plt.pcolormesh for better color alignment.

4

Display the heatmap

Use plt.show() to display the heatmap plot.

Matplotlib

import matplotlib.pyplot as plt

temperatures = [[22, 21, 23, 24, 25, 26, 27], [18, 19, 20, 21, 22, 23, 24], [30, 29, 28, 27, 26, 25, 24]]
days = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
cities = ['CityA', 'CityB', 'CityC']

plt.pcolormesh(temperatures, shading='auto')
plt.xticks(ticks=range(len(days)), labels=days)
plt.yticks(ticks=range(len(cities)), labels=cities)
plt.colorbar()
# Your code here

Need a hint?

Use plt.show() to see the heatmap window.