Python matplotlib pyplot module always draws on existing figure window when figure title is the same - python-3.x

Question

I am a new python user but an experienced Matlab user. I am recently debugging a python script, and when I manually re-run the script multiple times, I found a somewhat annoying issue of matplotlib: it always draws on existing figure window, overlapping on existing plot, if the figure title is the same.
The script I am debugging looks like this:
import matplotlib.pyplot as plt
# Some calculations here
plt.figure('Results') # The script will only create one figure
# plot the data
# End of the script
A simple search on Google shows that if I don't explicitly specify figure title, or give each figure a different handle, matplotlib can create separate figure windows, and true, it works.
However, is there a way to create multiple figure windows with the same title, without giving them different handles (which in my case, I had to do it manually) in python? In Matlab it will always create separate figure window no matter what figure title you give it.

Answer 1

The argument to figure is an identifier. If it is left empty anew figure will be created, else the figure with that identifier will be activiated. The documentation makes this rather clear:
matplotlib.pyplot.figure(num=None, ...)
num : integer or string, optional, default: none
If not provided, a new figure will be created, and the figure number will be incremented. The figure objects holds this number in a number attribute. If num is provided, and a figure with this id already exists, make it active, and returns a reference to it. If this figure does not exists, create it and returns it. If num is a string, the window title will be set to this figure’s num.
Hence in order to create a new figure, leave this argument out or specify differing ones. In order to set the window's title, use set_window_title.
The following will create two figures with the same window title.
import matplotlib.pyplot as plt
plt.figure()
plt.gcf().canvas.set_window_title('Results')
plt.plot([1,2,3])
plt.figure()
plt.gcf().canvas.set_window_title('Results')
plt.plot([2,3,1], color="crimson")
plt.show()

Answer 2

From the first paragraph of your question, ...
when I manually re-run the script multiple times, I found a somewhat
annoying issue of matplotlib: it always draws on existing figure
window
I think that simply clearing the figure (at the start of the script) would make your repeated runs of the script useable.
import matplotlib.pyplot as plt
# compute results here - random here as a standin.
import numpy as np
x = np.random.randn(500)
plt.figure("Results"); plt.clf()
# plot results here...
plt.hist(x, bins=20, histtype='step')
Now, each time you run the script, you will draw the results on a blank canvas and not over the top of the old results.
The figures below illustrate the difference, after 3 runs of the script (in ipython): left - without the plt.clf(), and right - with plt.clf() at the start.