Store values in a variable (or list) by clicking in the plot using Matplotlib in Python

 Code:

import numpy as np

import matplotlib.pyplot as plt

def onclick(event):

    global values

    values.append([event.xdata, event.ydata])

values = []

x = np.arange(0,10,1)

y = np.arange(0,10,1)

fig, ax = plt.subplots()

plt.scatter(x,y)

fig.canvas.mpl_connect('button_press_event', onclick)

plt.show(block=False)

plt.pause(5)

plt.close()

Explanation:

First we have to write a function to get values by clicking in the plot. That is:

def onclick(event):

    global values

    values.append([event.xdata, event.ydata])

The following syntax helps to pick data from the plot:

fig.canvas.mpl_connect('button_press_event', onclick)

We need to define a list outside the function to save the values. That is

values = []

and declare it as a global variable inside the function. That is

global values

and append values to the variable inside the function. That is

values.append([event.xdata, event.ydata])

We need to pause plot for sometime to get values saved in the variable. For that the following script is used:

plt.show(block=False)

plt.pause(5)

plt.close()

Here, plot will the open for 5 seconds. You can also increase the time by changing the value in plt.pause().

If you any questions, please comment here.