Permit covariance of key type in read_csv converters argument

Author: gandhis1

pandas-stubs/io/parsers/readers.pyi

@@ -48,7 +48,10 @@ def read_csv(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,
@@ -111,7 +114,10 @@ def read_csv(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,
@@ -174,7 +180,10 @@ def read_csv(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,
@@ -237,7 +246,10 @@ def read_table(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,
@@ -300,7 +312,10 @@ def read_table(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,
@@ -363,7 +378,10 @@ def read_table(
     | None = ...,
     dtype: DtypeArg | defaultdict | None = ...,
     engine: CSVEngine | None = ...,
-    converters: dict[int | str, Callable[[str], Any]] | None = ...,
+    converters: dict[int | str, Callable[[str], Any]]
+    | dict[int, Callable[[str], Any]]
+    | dict[str, Callable[[str], Any]]
+    | None = ...,
     true_values: list[str] = ...,
     false_values: list[str] = ...,
     skipinitialspace: bool = ...,

tests/test_frame.py

@@ -19,6 +19,7 @@
     List,
     Mapping,
     Tuple,
+    TypedDict,
     TypeVar,
     Union,
 )
@@ -1278,6 +1279,46 @@ def test_read_csv() -> None:
             pd.DataFrame,
         )
 
+        # Allow a variety of dict types for the converters parameter
+        converters1 = {"A": lambda x: str, "B": lambda x: str}
+        check(
+            assert_type(pd.read_csv(path, converters=converters1), pd.DataFrame),
+            pd.DataFrame,
+        )
+        converters2 = {"A": lambda x: str, "B": lambda x: float}
+        check(
+            assert_type(pd.read_csv(path, converters=converters2), pd.DataFrame),
+            pd.DataFrame,
+        )
+        converters3 = {0: lambda x: str, 1: lambda x: str}
+        check(
+            assert_type(pd.read_csv(path, converters=converters3), pd.DataFrame),
+            pd.DataFrame,
+        )
+        converters4 = {0: lambda x: str, 1: lambda x: float}
+        check(
+            assert_type(pd.read_csv(path, converters=converters4), pd.DataFrame),
+            pd.DataFrame,
+        )
+        converters5: dict[int | str, Callable[[str], Any]] = {
+            0: lambda x: str,
+            "A": lambda x: float,
+        }
+        check(
+            assert_type(pd.read_csv(path, converters=converters5), pd.DataFrame),
+            pd.DataFrame,
+        )
+
+        class ReadCsvKwargs(TypedDict):
+            converters: dict[int, Callable[[str], Any]]
+
+        read_csv_kwargs: ReadCsvKwargs = {"converters": {0: int}}
+
+        check(
+            assert_type(pd.read_csv(path, **read_csv_kwargs), pd.DataFrame),
+            pd.DataFrame,
+        )
+
 
 def test_groupby_series_methods() -> None:
     df = pd.DataFrame({"x": [1, 2, 2, 3, 3], "y": [10, 20, 30, 40, 50]})