type transpose

Author: MarcoGorelli

pandas-stubs/core/arrays/sparse/array.pyi

@@ -1,8 +1,11 @@
+from typing import Any
+
 import numpy as np
 from pandas.core.arrays import (
     ExtensionArray,
     ExtensionOpsMixin,
 )
+from typing_extensions import Self
 
 class SparseArray(ExtensionArray, ExtensionOpsMixin):
     def __init__(
@@ -53,7 +56,7 @@ class SparseArray(ExtensionArray, ExtensionOpsMixin):
     def sum(self, axis: int = ..., *args, **kwargs): ...
     def cumsum(self, axis: int = ..., *args, **kwargs): ...
     def mean(self, axis: int = ..., *args, **kwargs): ...
-    def transpose(self, *axes): ...
+    def transpose(self, *axes: Any) -> Self: ...
     @property
     def T(self): ...
     def __array_ufunc__(self, ufunc, method, *inputs, **kwargs): ...

pandas-stubs/core/base.pyi

@@ -44,7 +44,7 @@ class SelectionMixin(Generic[NDFrameT]):
 
 class IndexOpsMixin(OpsMixin, Generic[S1]):
     __array_priority__: int = ...
-    def transpose(self, *args, **kwargs) -> Self: ...
+    def transpose(self, axes: None = ...) -> Self: ...
     @property
     def T(self) -> Self: ...
     @property

pandas-stubs/core/frame.pyi

@@ -655,7 +655,7 @@ class DataFrame(NDFrame, OpsMixin, _GetItemHack):
         show_counts: bool | None = ...,
     ) -> None: ...
     def memory_usage(self, index: _bool = ..., deep: _bool = ...) -> Series: ...
-    def transpose(self, *args, copy: _bool = ...) -> Self: ...
+    def transpose(self, axes: None = ..., /, copy: _bool = ...) -> Self: ...
     @property
     def T(self) -> Self: ...
     def __getattr__(self, name: str) -> Series: ...

pandas-stubs/core/series.pyi

@@ -1598,7 +1598,7 @@ class Series(IndexOpsMixin[S1], NDFrame):
         bins: int | None = ...,
         dropna: _bool = ...,
     ) -> Series[float]: ...
-    def transpose(self, *args, **kwargs) -> Series[S1]: ...
+    def transpose(self, axes: None = ...) -> Series[S1]: ...
     @property
     def T(self) -> Self: ...
     # The rest of these were left over from the old

tests/test_frame.py

@@ -3854,3 +3854,10 @@ def test_hashable_args() -> None:
 # GH 906
 @pd.api.extensions.register_dataframe_accessor("geo")
 class GeoAccessor: ...
+
+
+def test_transpose() -> None:
+    df = pd.DataFrame({"a": [1, 1, 2], "b": [4, 5, 6]})
+    check(assert_type(df.transpose(), pd.DataFrame), pd.DataFrame)
+    check(assert_type(df.transpose(None), pd.DataFrame), pd.DataFrame)
+    check(assert_type(df.transpose(copy=True), pd.DataFrame), pd.DataFrame)

tests/test_indexes.py

@@ -1201,3 +1201,10 @@ def test_disallow_empty_index() -> None:
     # From GH 826
     if TYPE_CHECKING_INVALID_USAGE:
         i0 = pd.Index()  # type: ignore[call-overload] # pyright: ignore[reportCallIssue]
+
+
+def test_transpose() -> None:
+    idx: pd.Index[int] = pd.Index([1, 1, 2])
+    check(assert_type(idx.transpose(), "pd.Index[int]"), pd.Index, np.int64)
+    check(assert_type(idx.transpose(None), "pd.Index[int]"), pd.Index, np.int64)
+    check(assert_type(idx.transpose(axes=None), "pd.Index[int]"), pd.Index, np.int64)

tests/test_series.py

@@ -3552,3 +3552,10 @@ def test_series_int_float() -> None:
     check(
         assert_type(pd.Series([1, 2.0, 3]), "pd.Series[float]"), pd.Series, np.float64
     )
+
+
+def test_transpose() -> None:
+    s: pd.Series[int] = pd.Series([1, 1, 2])
+    check(assert_type(s.transpose(), "pd.Series[int]"), pd.Series, np.int64)
+    check(assert_type(s.transpose(None), "pd.Series[int]"), pd.Series, np.int64)
+    check(assert_type(s.transpose(axes=None), "pd.Series[int]"), pd.Series, np.int64)