Change matplotlib line style in mid-graph

Prerequisite: Matplotlib

In this article we will learn how to change line style in mid-graph using matplotlib in Python.

• Matplotlib: It is a tremendous visualization library in Python for 2D plots of arrays. Matplotlib may be a multi-platform data visualization library built on NumPy arrays and designed to figure with the broader SciPy stack. It was introduced by John Hunter within the year 2002.
• Line style: Line style is a feature that describes in which fashion or style line is drawn. Following image shows the key that has to provided as input parameter and what line style it will produce:

Approach:

1. Import the matplotlib.pyplot library and other for data (optional)
2. Import or create some data
3. Draw a graph plot with different line style is middle.

Example 1:

In this example we will use simple steps mentioned above and form a graph with two different line styles.

Python3

# importing packages
import matplotlib.pyplot as plt
import numpy as np

# create data
x = np.linspace(0, 10, 100)
y = 3 * x + 2

below = y < 15
above = y >= 15

# Plot lines below as dotted-------
plt.plot(x[below], y[below], '--')

# Plot lines above as solid________
plt.plot(x[above], y[above], '-')

plt.show()

Output :

Example 2 :

In this example we will use simple steps mentioned above and form a graph with two different line styles in one sine function.

Python3

# importing packages
import matplotlib.pyplot as plt
import numpy as np

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

below = y < .5
above = y >= .5

# Plot lines below as dotted-------
plt.plot(x[below], y[below], '--')

# Plot lines above as solid_______
plt.plot(x[above], y[above], '-')

plt.show()

Output :

Example 3 :

This is similar to above example with extra cosine function to show different feature of line styles in mid graph.

Python3

# importing packages
import matplotlib.pyplot as plt
import numpy as np

# create data
x = np.linspace(0, 10, 100)
y1 = np.sin(x)
y2 = np.cos(x)

below = abs(y1-y2) < .2
above = abs(y1-y2) >= .2

# Plot lines below as dotted-------
plt.plot(x[below], y1[below], 'r--')

# Plot lines below as dotted-------
plt.plot(x[below], y2[below], 'g--')

# Plot lines above as solid_______
plt.plot(x[above], y1[above], 'r-')

# Plot lines above as solid_______
plt.plot(x[above], y2[above], 'g-')

plt.show()

Output :