Documentation Link

https://matplotlib.org/stable/users/whats_new.html#changes-to-behavior-of-axes-creation-methods-gca-add-axes-add-subplot

Problem

In version 3.4, passing keyword arguments to plt.gca() was deprecated. I was previously using plt.gca(projection='polar') to:

1. Check if a polar projection axes exists, and if so return it
2. If not, create a new axes with a polar projection

Looking at the documentation (https://matplotlib.org/stable/users/whats_new.html#changes-to-behavior-of-axes-creation-methods-gca-add-axes-add-subplot) it's not clear to me how to replicate this behaviour however. In pseudo-code I think what I want to do is:

if len(pyplot_axes):
    if plt.gca().name != 'polar':
        raise RuntimeError('Axes isn't polar projection')
    else:
        return plt.gca()
else:
    return plt.subplot(projection='polar')

The only thing I don't know how to get is a list of pyplot axes (pyplot_axes above). I looked at https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.html and didn't see anything, but perhaps there's another page I'm missing?

Suggested improvement

Add a clear description to the changelog (https://matplotlib.org/stable/users/whats_new.html#changes-to-behavior-of-axes-creation-methods-gca-add-axes-add-subplot) showing how to write code to reproduce plt.gca(projection=...).

Matplotlib Version

3.4.2

Matplotlib documentation version

3.4.2