Add the ability to save the plot

[joanna-janos]

No description provided.

[NaleRaphael]

Hi @joanna-janos , thanks for your contribution.

Before @davidtvs reviewes this PR, you may note that this package still needs to support Python 2.7. However, the builtin module pathlib you used was introduced since Python 3.4.
Therefore, you might need to change the code to make it compatible with Python 2.7.

[joanna-janos]

Hi @NaleRaphael,

sorry for that, I have changed code to make it compatible with python 2.7 (use os instead of pathlib)

[NaleRaphael]

Don't be sorry, this is a nice improvement!
Here is a change request, could you please check that?

[NaleRaphael]

It would be better to use os.makedirs instead of os.mkdir for multi-layer directory.
Otherwise, you have to use try...except to handle FileNotFoundError here.
(In my opinion, os.makedirs is better for user experience)

[davidtvs]

I would prefer to do this by returning the matplotlib figure and axes. The user can then choose if he wants to save and how he wants to do it. This way there's no additional parameter, no extra code on our side, and it's also more flexible for the user (plot can be manipulated and then saved in whatever way the user wants)

[NaleRaphael]

@davidtvs You're right, this approach is much more flexible!
BTW, it seems that plt.gcf() is another approach for user to get the handler of latest generated figure.
But it would be much more difficult than just returning the handler to user.

[davidtvs]

@joanna-janos thanks for bringing this to our attention. I'm closing this PR but feel free to open a new one that returns the figure and the axis from plot

[davidtvs]

FYI, the commit 70b6c1f implements the functionality that I described above.

@joanna-janos to save the figure you can now do:

# Create the figure and axes object outside and pass the axes to lr_finder.plot
fig, ax = plt.subplots()
lr_finder.plot(ax=ax)

# ax can be further manipulated by the user after lr_finder.plot

fig.savefig("test.png")

Note that when you pass the Axes object to lr_finder.plot() the figure is not shown (no plt.show()) to avoid destroying the figure before you can save it.