René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Doc]: How to replicate behaviour of `plt.gca(projection=...)`?","articleBody":"### Documentation Link\n\nhttps://matplotlib.org/stable/users/whats_new.html#changes-to-behavior-of-axes-creation-methods-gca-add-axes-add-subplot\n\n### Problem\n\nIn version 3.4, passing keyword arguments to `plt.gca()` was deprecated. I was previously using `plt.gca(projection='polar')` to:\r\n\r\n1. Check if a polar projection axes exists, and if so return it\r\n2. If not, create a new axes with a polar projection\r\n\r\nLooking 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:\r\n```python\r\nif len(pyplot_axes):\r\n    if plt.gca().name != 'polar':\r\n        raise RuntimeError('Axes isn't polar projection')\r\n    else:\r\n        return plt.gca()\r\nelse:\r\n    return plt.subplot(projection='polar')\r\n```\r\nThe 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?\n\n### Suggested improvement\n\nAdd 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=...)`.\n\n### Matplotlib Version\n\n3.4.2\n\n### Matplotlib documentation version\n\n3.4.2","author":{"url":"https://github.com/dstansby","@type":"Person","name":"dstansby"},"datePublished":"2021-07-30T13:18:10.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/20770/matplotlib/issues/20770"}