Matplotlib.pyplot.twinx() in Python

Last Updated : 11 Apr, 2020

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

Sample Code

# sample code 
import matplotlib.pyplot as plt  
    
plt.plot([1, 2, 3, 4], [16, 4, 1, 8])  
plt.show()  

Output:

matplotlib.pyplot.twinx() Function

The twinx() function in pyplot module of matplotlib library is used to make and return a second axes that shares the x-axis.

Syntax:
matplotlib.pyplot.twinx(ax=None)
Parameters: This method does not accepts any parameters.

Returns: This returns the second axes that shares the x-axis

Below examples illustrate the matplotlib.pyplot.twinx() function in matplotlib.pyplot:

Example #1:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import numpy as np 
   
   
def GFG1(temp): 
    return (5. / 9.) * (temp - 32) 
   
def GFG2(ax1): 
    y1, y2 = ax1.get_ylim() 
    ax_twin .set_ylim(GFG1(y1), GFG1(y2)) 
    ax_twin .figure.canvas.draw() 
   
fig, ax1 = plt.subplots() 
ax_twin = ax1.twinx() 
   
ax1.callbacks.connect("ylim_changed", GFG2) 
ax1.plot(np.linspace(0, 120, 100)) 
ax1.set_xlim(30, 100) 
   
ax1.set_ylabel('Fahrenheit') 
ax_twin .set_ylabel('Celsius') 
   
fig.suptitle('matplotlib.pyplot.twinx() function \ 
Example\n\n', fontweight ="bold") 
plt.show() 

Output:

Example #2:

# Implementation of matplotlib function 
import numpy as np 
import matplotlib.pyplot as plt 
   
# Create some mock data 
t = np.arange(0.01, 20.0, 0.001) 
data1 = np.exp(t) 
data2 = np.sin(0.3 * np.pi * t) 
   
fig, ax1 = plt.subplots() 
   
color = 'tab:blue'
ax1.set_xlabel('time (s)') 
ax1.set_ylabel('exp', color = color) 
ax1.plot(t, data1, color = color) 
ax1.tick_params(axis ='y', labelcolor = color) 
   
ax2 = ax1.twinx() 
   
color = 'tab:green'
ax2.set_ylabel('sin', color = color) 
ax2.plot(t, data2, color = color) 
ax2.tick_params(axis ='y', labelcolor = color) 
  
fig.suptitle('matplotlib.pyplot.twinx() function \ 
Example\n\n', fontweight ="bold") 
plt.show() 