Python:Matplotlib .axis()

The .axis() function in Matplotlib’s pyplot module gets or sets properties of the plot axes, including axis limits, aspect ratio, and visibility.

Syntax

matplotlib.pyplot.axis(arg=None, emit=True, **kwargs)

The function can be called in several ways:

• axis(): Returns current axis limits as (xmin, xmax, ymin, ymax)
• axis([xmin, xmax, ymin, ymax]): Sets axis limits
• axis(option): Sets axis properties using predefined options
• axis(**kwargs): Sets axis properties using keyword arguments

Parameters:

• arg (optional): Defines how the axes are set or displayed. Accepts the following values:
  • A list or tuple [xmin, xmax, ymin, ymax] to set axis limits.
  • 'off' to hide the axes.
  • 'on' to show the axes.
  • 'equal', 'scaled', 'tight', 'auto', 'image', 'square' — control axis scaling and aspect ratio.
• emit (bool, default: True): If True, notifies observers of axis limit changes.
• kwargs (optional): Additional axis properties such as xmin, xmax, ymin, and ymax.

Return value:

Returns a tuple (xmin, xmax, ymin, ymax) representing the current axis limits.

Example 1: Using .axis() to Control Axis Properties

This example creates three subplots demonstrating different axis control modes. The first subplot uses axis([2, 8, -0.5, 0.5]) to restrict the view to specific x and y ranges. The second subplot uses axis('equal') to ensure both axes use the same scale. The third subplot uses axis('off') to hide the axis lines, ticks, and labels:

import matplotlib.pyplot as plt
import numpy as np

# Generate sample data
x = np.linspace(0, 10, 100)
y = np.sin(x)

# Create a basic plot
plt.figure(figsize=(10, 4))

# Subplot 1: Custom axis limits
plt.subplot(1, 3, 1)
plt.plot(x, y)
plt.axis([2, 8, -0.5, 0.5])
plt.title('Custom Limits')
plt.grid(True, alpha=0.3)

# Subplot 2: Equal aspect ratio
plt.subplot(1, 3, 2)
plt.plot(x, y)
plt.axis('equal')
plt.title('Equal Scaling')
plt.grid(True, alpha=0.3)

# Subplot 3: Axis turned off
plt.subplot(1, 3, 3)
plt.plot(x, y)
plt.axis('off')
plt.title('Hidden Axes')

plt.tight_layout()
plt.show()

Copy to clipboard
Copy to clipboard

The output of this code is:

Example 2: Getting and Setting Axis Limits

This example demonstrates how to set custom axis limits and retrieve the current limits. The axis() function is called with a list of four values to set the x and y axis ranges, then called without arguments to return the current limits as a tuple.

import matplotlib.pyplot as plt
import numpy as np

# Create data
x = np.linspace(0, 2*np.pi, 100)
y = np.sin(x)

# Create plot
plt.plot(x, y, linewidth=2)
plt.title('Sine Wave with Custom Axes')

# Set custom axis limits
plt.axis([0, 2*np.pi, -1.5, 1.5])

# Get and print current axis limits
limits = plt.axis()
print(f"Current axis limits: {limits}")

plt.grid(True, alpha=0.3)
plt.show()

Copy to clipboard
Copy to clipboard

The output of this code is: