Live figure with jupyter notebook (or pure python file) using matplotlib

bridget462

bridget462

Posted on September 27, 2020

Live figure with jupyter notebook (or pure python file) using matplotlib

Source Codes: https://github.com/bridget462/live-figure

To make a live graph, which update constantly to reflect real-time data, use following method instead of normal plt.show()

The Key methods for live graph are:

  • plt.draw(): to display plot
  • plt.pause(): keep displaying current frame certain duration
  • plt.cla(): to clear previous frame

Use methods above in loop to constantly update figure.


Codes

we only use 2 libraries

import numpy as np # to generate random data
import matplotlib.pyplot as plt # to make figure

# optional (just for figure appearence)
plt.style.use('seaborn-colorblind')
plt.style.use('seaborn-whitegrid')

print('library imported')

if using jupyter, excute command below to create intractive figure instead of displaying in the jupyter cell.

%matplotlib qt

To make live figure, use key methods explained above in loop to update figures. Also replace random number with your actual data.

MEASUREMENT_TIME = 50
INTERVAL_SEC = 0.1

for i in range(MEASUREMENT_TIME):
    # replace with your data
    data = np.random.rand(100)

    plt.plot(data)

    # figure appearence adjustments
    plt.ylim(-0.2, 1.2)
    plt.title(f'FRAME {i+1}')

    # to avoid clearing last plot
    if (i != MEASUREMENT_TIME-1):
        plt.draw()
        plt.pause(INTERVAL_SEC)
        plt.cla()
    else:
        plt.show()

And that's about it. plt.draw(), plt.pause(), plt.cla() can be used to any other figures, such as 3D, polar and etc.

💖 💪 🙅 🚩
bridget462
bridget462

Posted on September 27, 2020

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