BUG: DataFrame.explode fails with str dtype

[rhshadrach]

• closes #xxxx (Replace xxxx with the GitHub issue number)
• 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.

This operation works on all other dtypes, e.g.

df = pd.DataFrame({"a": [1, 2]})
print(df.explode(column="a"))
#    a
# 0  1
# 1  2

[datapythonista]

Looks good. I'd personally have the new release notes template added in a separate issue, but no big deal.

Btw, did we have problems before to have the result is not df assert? I haven't used it before, it'd be good to understand in which tests it make sense. Thanks!

[rhshadrach]

@datapythonista

Btw, did we have problems before to have the result is not df assert? I haven't used it before, it'd be good to understand in which tests it make sense. Thanks!

I think it makes sense to check this when we have a no-op that should return a copy. If the operation modifies the data (which is the case for the vast majority of tests), I don't think it needs to be checked.

[rhshadrach]

@datapythonista - fixed up the docs build, this should be ready.

[jorisvandenbossche]

Thanks!

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 2.3.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 73db25d585a12e587beffef83449dbdd5d16d0f6

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #61623: BUG: DataFrame.explode fails with str dtype'

4. Push to a named branch:

git push YOURFORK 2.3.x:auto-backport-of-pr-61623-on-2.3.x

5. Create a PR against branch 2.3.x, I would have named this PR:

"Backport PR #61623 on branch 2.3.x (BUG: DataFrame.explode fails with str dtype)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[jorisvandenbossche]

Backport -> #61699