DOC: See also missing links in GroupBy.apply(), GroupBy.pipe()

[srvanrell]

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.core.groupby.GroupBy.pipe.html#pandas.core.groupby.GroupBy.pipe

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.core.groupby.GroupBy.pipe.html#pandas.core.groupby.GroupBy.apply

Problem description

GroupBy.apply() and GroupBy.pipe() have missing links in their See also section. Might be other missing links in other functions of GroupBy.

Specifically, the links that are not working are Series.apply, DataFrame.apply, Series.pipe, DataFrame.pipe

Expected Output

Links should take you to named functions

[srvanrell]

I would be glad to help but I don't know what is missing. On previous PRs I have solved this kind of issue completing the full signature of the linked function. If anyone can guide me to the solution I can propose a PR.

[alimcmaster1]

Looks like these are also broken in 0.25 https://pandas.pydata.org/pandas-docs/version/0.25/reference/api/pandas.core.groupby.GroupBy.pipe.html?highlight=groupby%20pipe#pandas.core.groupby.GroupBy.pipe

[srvanrell]

Does it has something to do with the Appender decorator?

pandas/pandas/core/groupby/groupby.py

Lines 701 to 748 in fd9ceb9

	@Appender(
	_apply_docs["template"].format(
	input="dataframe", examples=_apply_docs["dataframe_examples"]
	)
	)
	def apply(self, func, *args, **kwargs):
	func = self._is_builtin_func(func)
	# this is needed so we don't try and wrap strings. If we could
	# resolve functions to their callable functions prior, this
	# wouldn't be needed
	if args or kwargs:
	if callable(func):
	@wraps(func)
	def f(g):
	with np.errstate(all="ignore"):
	return func(g, *args, **kwargs)
	elif hasattr(nanops, "nan" + func):
	# TODO: should we wrap this in to e.g. _is_builtin_func?
	f = getattr(nanops, "nan" + func)
	else:
	raise ValueError(
	"func must be a callable if args or kwargs are supplied"
	)
	else:
	f = func
	# ignore SettingWithCopy here in case the user mutates
	with option_context("mode.chained_assignment", None):
	try:
	result = self._python_apply_general(f)
	except TypeError:
	# gh-20949
	# try again, with .apply acting as a filtering
	# operation, by excluding the grouping column
	# This would normally not be triggered
	# except if the udf is trying an operation that
	# fails on *some* columns, e.g. a numeric operation
	# on a string grouper column
	with _group_selection_context(self):
	return self._python_apply_general(f)
	return result

[alimcmaster1]

@datapythonista @jorisvandenbossche - I think this affects quite alot of the Docstrings in pandas.core.

Other examples where See Also links do not have a href would be (in addition to the above):

Resampler.aggregate and Resampler.asfreq. They cannot reference attributes in the top level pandas namespace. Whereas Resampler.interpolate looks fine.

One fix would be to update:

See Also
--------
DataFrame.pipe: Apply a function with arguments to a dataframe.

to

See Also
--------
pandas.DataFrame.pipe: Apply a function with arguments to a dataframe.

Wanted to get your thoughts on this as we don't do it elsewhere?

[datapythonista]

I think we should understand the problem instead of prefixing with pandas. Something must be wrong with sphinx. Afaik it saves all the pages first, and then uses that to generate the links.

Besides debugging that, we can check if it also fails with other versions of sphinx.

[srvanrell]

Another example of the same issue? DataFrame.aggregate