DEPR: Series.ravel

[marechaux]

• closes DEPR: Deprecate Series.ravel #52511
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[phofl]

I'll have to take a closer look here, looks like we are using this internally. Will get to this over the weekend. pr itself is good!

[marechaux]

Thanks for your answer, Should I replace the internal usage of this function ?

[phofl]

I'll have to check what we are doing before I can give you a definitiv answer here

[jorisvandenbossche]

One place where we use ravel() internally that seems to cause many of the failures is in maybe_downcast_numeric:

pandas/pandas/core/dtypes/cast.py

Lines 348 to 355 in 961f9c4

	if dtype.kind in "biu":
	if not result.size:
	# if we don't have any elements, just astype it
	return trans(result).astype(dtype)
	# do a test on the first element, if it fails then we are done
	r = result.ravel()
	arr = np.array([r[0]])

Changing r = result.ravel() to r = np.ravel(result) might be sufficient (assuming this won't dispatch to the method), or otherwise r = np.asarray(result).ravel() (we know at this point we have a numpy dtyped Series, so np.asarray(..) is cheap)

In theory we should not call this method with a Series though, but with an array (or, the type annotation is wrong)

[jbrockmendel]

Thanks for your answer, Should I replace the internal usage of this function ?

Yes.

In theory we should not call this method with a Series though, but with an array (or, the type annotation is wrong)

Agreed.

[phofl]

Two quick changes to get ci green (hopefully):

• in assert_is_valid_plot_return_object there is still a ravel on a Series object. I'd recommend calling np.asarray(obj) and call ravel on the array
• FAILED pandas/tests/copy_view/test_array.py::test_ravel_read_only[F] You have to use tm.assert_produces_warning here

[github-actions]

This pull request is stale because it has been open for thirty days with no activity. Please update and respond to this comment if you're still interested in working on this.

[mroeschke]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.