How to Create Subplots in Matplotlib: Simple Guide

Use matplotlib.pyplot.subplots() to create multiple plots in one figure. It returns a figure and axes array where you can plot individually. Customize layout by specifying rows and columns in subplots().

Syntax

The basic syntax to create subplots is:

• fig, axes = plt.subplots(nrows, ncols, figsize=(width, height))
• nrows and ncols define the grid size of subplots.
• figsize sets the figure size in inches.
• fig is the overall figure object.
• axes is an array or single Axes object to plot on.

python

fig, axes = plt.subplots(nrows=2, ncols=3, figsize=(10, 6))

Example

This example creates a 2x2 grid of subplots and plots simple line charts on each subplot.

python

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 10, 100)

fig, axes = plt.subplots(2, 2, figsize=(8, 6))

axes[0, 0].plot(x, np.sin(x))
axes[0, 0].set_title('Sine Wave')

axes[0, 1].plot(x, np.cos(x), 'r')
axes[0, 1].set_title('Cosine Wave')

axes[1, 0].plot(x, np.tan(x), 'g')
axes[1, 0].set_ylim(-10, 10)  # Limit y-axis for tan
axes[1, 0].set_title('Tangent Wave')

axes[1, 1].plot(x, x**2, 'm')
axes[1, 1].set_title('Quadratic')

plt.tight_layout()
plt.show()

Output

A window with 4 plots arranged in 2 rows and 2 columns showing sine, cosine, tangent (limited y-axis), and quadratic curves.

Common Pitfalls

Common mistakes when creating subplots include:

• Not unpacking axes correctly when only one subplot is created (it returns a single Axes, not an array).
• Indexing axes incorrectly when nrows or ncols is 1 (axes can be 1D array or single object).
• Forgetting to call plt.tight_layout() to avoid overlapping labels.

python

import matplotlib.pyplot as plt

# Wrong: axes is not an array if only one subplot
fig, axes = plt.subplots(1, 1)
# axes[0].plot([1, 2, 3])  # This will cause an error

# Right:
fig, ax = plt.subplots(1, 1)
ax.plot([1, 2, 3])
plt.show()

Output

A single plot showing points connected by lines without error.

Quick Reference

Tips for using plt.subplots():

• Use fig, axes = plt.subplots() to create multiple plots.
• Access subplots with axes[row, col] for 2D grids or axes[index] for 1D.
• Use figsize to control figure size.
• Call plt.tight_layout() to prevent overlap.
• For a single subplot, axes is a single Axes object, not an array.

Key Takeaways

Use plt.subplots(nrows, ncols) to create a grid of subplots in one figure.

Access each subplot via the axes array to plot different data.

Remember plt.tight_layout() to avoid overlapping plot elements.

For a single subplot, axes is not an array but a single object.

Set figsize to control the overall size of the subplot figure.