What Is a Scatter Plot in Matplotlib?

A scatter plot is a chart used to display individual data points on a graph.
It helps visualize the relationship, correlation, or distribution between two variables.

Scatter plots are commonly used in data science, statistics, and machine learning to identify trends and patterns.

Basic Scatter Plot Example

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] plt.scatter(x, y) plt.show()

Changing Marker Style

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] plt.scatter(x, y, marker="^") plt.show() # Output: # Scatter plot with triangle markers

Changing Color

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] plt.scatter(x, y, color="red") plt.show() # Output: # Scatter plot with red points

Multiple Colors Using List

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] colors = ["red", "blue", "green", "purple", "orange"] plt.scatter(x, y, c=colors) plt.show() # Output: # Scatter plot with different colored points

Adding Labels and Title

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] plt.scatter(x, y) plt.title("Student Scores") plt.xlabel("Hours Studied") plt.ylabel("Marks") plt.show() # Output: # Scatter plot with labels and title

Scatter Plot with Transparency

Python 
import matplotlib.pyplot as plt x = [1, 2, 3, 4, 5] y = [2, 4, 1, 8, 7] plt.scatter(x, y, alpha=0.5) plt.show() # Output: # Semi-transparent points

alpha controls opacity.

Comparing Two Datasets

Python 
import matplotlib.pyplot as plt x1 = [1,2,3,4] y1 = [4,3,2,1] x2 = [1,2,3,4] y2 = [1,2,3,4] plt.scatter(x1, y1, color="red") plt.scatter(x2, y2, color="blue") plt.show() # Output: # Two colored scatter datasets

Key Points to Remember

  • Scatter plots show relationships between variables.

  • Use plt.scatter() to create them.

  • Customize with marker, color, s, and alpha.

  • Useful for correlation and trend analysis.