python - When is plt.show() required to show a plot and when is it not?

Question

Since the following code will show a plot without plt.show(), what is the point of plt.show()?

Please tell me when plt.show() is required as this would allow me to appreciate the intricacy of matplotlib better.

N.B.: I'm using this in Spyder (Anaconda)

import matplotlib.pyplot as plt
plt.subplot(211)             # the first subplot in the first figure
plt.plot([1, 2, 3])

Answer 1

To require or not required depending on where your script is.

There are 2 contexts.

1. Matplotlib is used in a terminal or scripts, plt.show() is a must.

2. Matplotlib is used in a IPython shell or a notebook (ex: Kaggle), plt.show() is unnecessary.