DataFrame.drop with columns=set(...) is unspecified

[cmp0xff]

Describe the bug

DataFrame.drop with columns=set(...) is unspecified.

To Reproduce

1. Provide a minimal runnable pandas example that is not properly checked by the stubs.

import pandas as pd

df = pd.DataFrame({1: [2], 3: [4]})
df = df.drop(columns={1})

2. I am using mypy type checker.
3. The error message received from that type checker.

df_drop.py:4:6: error: No overload variant of "drop" of "NDFrame" matches argument type "set[int]"  [call-overload]
df_drop.py:4:6: note: Possible overload variants:
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any] = ..., columns: Hashable | Sequence[Hashable] | Index[Any], level: Hashable | int | None = ..., inplace: Literal[True], errors: Literal['ignore', 'raise'] = ...) -> None
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any], columns: Hashable | Sequence[Hashable] | Index[Any] = ..., level: Hashable | int | None = ..., inplace: Literal[True], errors: Literal['ignore', 'raise'] = ...) -> None
df_drop.py:4:6: note:     def drop(self, labels: Hashable | Sequence[Hashable] | Index[Any], *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: None = ..., columns: None = ..., level: Hashable | int 
| None = ..., inplace: Literal[True], errors: Literal['ignore', 'raise'] = ...) -> None
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any] = ..., columns: Hashable | Sequence[Hashable] | Index[Any], level: Hashable | int | None = ..., inplace: Literal[False] = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any], columns: Hashable | Sequence[Hashable] | Index[Any] = ..., level: Hashable | int | None = ..., inplace: Literal[False] = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame
df_drop.py:4:6: note:     def drop(self, labels: Hashable | Sequence[Hashable] | Index[Any], *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: None = ..., columns: None = ..., level: Hashable | int 
| None = ..., inplace: Literal[False] = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any] = ..., columns: Hashable | Sequence[Hashable] | Index[Any], level: Hashable | int | None = ..., inplace: bool = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame | None
df_drop.py:4:6: note:     def drop(self, labels: None = ..., *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: Hashable | Sequence[Hashable] | Index[Any], columns: Hashable | Sequence[Hashable] | Index[Any] = ..., level: Hashable | int | None = ..., inplace: bool = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame | None
df_drop.py:4:6: note:     def drop(self, labels: Hashable | Sequence[Hashable] | Index[Any], *, axis: Literal['index', 0] | Literal['columns', 1] = ..., index: None = ..., columns: None = ..., level: Hashable | int 
| None = ..., inplace: bool = ..., errors: Literal['ignore', 'raise'] = ...) -> DataFrame | None
Found 1 error in 1 file (checked 1 source file)

Please complete the following information

• OS: Windows
• OS Version:

[System.Environment]::OSVersion.Version

Major  Minor  Build  Revision
-----  -----  -----  --------
10     0      19045  0

• python version: Python 3.11.9
• version of type checker: mypy 1.11.2 (compiled: yes)
• version of installed pandas-stubs: pandas-stubs==2.2.2.240807

Additional context

Nope

[Dr-Irv]

First, your example is not correct. It should be:

import pandas as pd

df = pd.DataFrame({1: [2], 3: [4]})   # Fix is here
df = df.drop(columns={1})

Secondly, the pandas documentation says that the argument for columns is "single label or list-like". While your code works, it is not clear that it should. The stubs follows what is documented and a set is not "list-like".

I've added a reference to a pandas issue pandas-dev/pandas#59890 to see what the pandas developers say there.

[Dr-Irv]

based on discussion at dev meeting on 2/26/2025: modify docs to say that any Iterable is acceptable so stubs should say the same

[cmp0xff]

based on discussion at dev meeting on 2/26/2025: modify docs to say that any Iterable is acceptable so stubs should say the same

Hi, thank you for following up the issue in the dev meeting. However I believe stub is also to be fixed, so that mypy won't raise an error upon encountering an Iterable.

[Dr-Irv]

based on discussion at dev meeting on 2/26/2025: modify docs to say that any Iterable is acceptable so stubs should say the same

Hi, thank you for following up the issue in the dev meeting. However I believe stub is also to be fixed, so that mypy won't raise an error upon encountering an Iterable.

Ooops. Typo on my part. Yes, the stubs need to be modified.