Clean: Categorical.fillna NaN in categories checking

[TomAugspurger]

We don't allow NaN in the categories anymore, so this block should be unreachable.

pandas/pandas/core/arrays/categorical.py

Lines 1622 to 1628 in 8bfcddc

	# Make sure that we also get NA in categories
	if self.categories.dtype.kind in ['S', 'O', 'f']:
	if np.nan in self.categories:
	values = values.copy()
	nan_pos = np.where(isna(self.categories))[0]
	# we only have one NA in categories
	values[values == nan_pos] = -1

If anyone wants to remove it and test things out.

[bhavybarca]

hi i would like to contribute to this issue.
P.S. - I am a beginner

[TomAugspurger]

Hi @bhavybarca, I think #19880 beat you to it.

good first issue has some other good first issues if you want to find one no one is working on.

[bhavybarca]

i have basic knowledge of python and pandas,could you suggest some good first issues.
thanks