Matplotlib Fill Betweenx

Introduction

Matplotlib is a data visualization library in Python. It provides a wide variety of tools to create complex and customizable plots, charts, and graphs. One of the most useful tools provided by Matplotlib is the fill_betweenx function. This function is used to fill the area between two horizontal curves. In this tutorial, we will explore the fill_betweenx function and learn how to use it to create different types of plots.

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Skills Graph

Plotting Simple Fill Betweenx

In this step, we will learn how to use the fill_betweenx function to create a simple plot. We will fill the area between two curves.

import matplotlib.pyplot as plt
import numpy as np

y = np.arange(0.0, 2, 0.01)
x1 = np.sin(2 * np.pi * y)
x2 = 1.2 * np.sin(4 * np.pi * y)

fig, ax = plt.subplots(figsize=(6, 6))

ax.fill_betweenx(y, x1, x2, color='green', alpha=0.5)
ax.plot(x1, y, color='blue')
ax.plot(x2, y, color='red')

plt.show()

Creating Multiple Subplots

In this step, we will learn how to create multiple subplots and use the fill_betweenx function to fill the area between two horizontal curves in each subplot.

import matplotlib.pyplot as plt
import numpy as np

y = np.arange(0.0, 2, 0.01)
x1 = np.sin(2 * np.pi * y)
x2 = 1.2 * np.sin(4 * np.pi * y)

fig, [ax1, ax2, ax3] = plt.subplots(1, 3, sharey=True, figsize=(12, 4))

ax1.fill_betweenx(y, 0, x1, color='green', alpha=0.5)
ax1.plot(x1, y, color='blue')
ax1.set_title('Fill between (x1, 0)')

ax2.fill_betweenx(y, x1, 1, color='red', alpha=0.5)
ax2.plot(x1, y, color='blue')
ax2.set_title('Fill between (x1, 1)')

ax3.fill_betweenx(y, x1, x2, color='orange', alpha=0.5)
ax3.plot(x1, y, color='blue')
ax3.plot(x2, y, color='red')
ax3.set_title('Fill between (x1, x2)')

plt.show()

Using Logical Conditions

In this step, we will learn how to use logical conditions to fill the area between two horizontal curves.

import matplotlib.pyplot as plt
import numpy as np

y = np.arange(0.0, 2, 0.01)
x1 = np.sin(2 * np.pi * y)
x2 = 1.2 * np.sin(4 * np.pi * y)

fig, ax = plt.subplots(figsize=(6, 6))

ax.plot(x1, y, color='black')
ax.plot(x2, y, color='black')

ax.fill_betweenx(y, x1, x2, where=x2 >= x1, facecolor='green', alpha=0.5)
ax.fill_betweenx(y, x1, x2, where=x2 <= x1, facecolor='red', alpha=0.5)

plt.show()

Using Masked Arrays

In this step, we will learn how to use masked arrays to fill the area between two horizontal curves.

import matplotlib.pyplot as plt
import numpy as np

y = np.arange(0.0, 2, 0.01)
x1 = np.sin(2 * np.pi * y)
x2 = 1.2 * np.sin(4 * np.pi * y)
x2 = np.ma.masked_greater(x2, 1.0)

fig, ax = plt.subplots(figsize=(6, 6))

ax.plot(x1, y, color='black')
ax.plot(x2, y, color='black')

ax.fill_betweenx(y, x1, x2, where=x2 >= x1, facecolor='green', alpha=0.5)
ax.fill_betweenx(y, x1, x2, where=x2 <= x1, facecolor='red', alpha=0.5)

plt.show()

Summary

In this tutorial, we learned how to use the fill_betweenx function in Matplotlib to fill the area between two horizontal curves. We also learned how to create multiple subplots and use logical conditions and masked arrays to create different types of plots. By using the fill_betweenx function, we can create complex and customizable plots in Python.