ENH: Improve to_csv and from_{fwf,csv,table}

pandas-stubs/_libs/lib.pyi

@@ -1,3 +1,8 @@
+from enum import Enum
+
 no_default = None
 
+class NoDefault(Enum):
+    no_default: int
+
 def infer_dtype(value: object, skipna: bool = ...) -> str: ...

pandas-stubs/_typing.pyi

@@ -14,6 +14,7 @@ from typing import (
     AnyStr,
     Callable,
     Hashable,
+    Iterator,
     Literal,
     Mapping,
     Optional,
@@ -65,6 +66,12 @@ class BaseBuffer(Protocol): ...
 class ReadBuffer(BaseBuffer, Protocol[AnyStr_cov]): ...
 class WriteBuffer(BaseBuffer, Protocol[AnyStr_cov]): ...
 
+class ReadCsvBuffer(ReadBuffer[AnyStr_cov], Protocol[AnyStr_cov]):
+    def __iter__(self) -> Iterator[AnyStr_cov]: ...
+    def readline(self) -> AnyStr_cov: ...
+    @property
+    def closed(self) -> bool: ...
+
 FilePath = Union[str, PathLike[str]]
 
 Buffer = Union[IO[AnyStr], RawIOBase, BufferedIOBase, TextIOBase, TextIOWrapper, mmap]
@@ -238,6 +245,9 @@ CSVEngine = Literal["c", "python", "pyarrow", "python-fwf"]
 
 HDFCompLib = Literal["zlib", "lzo", "bzip2", "blosc"]
 ParquetEngine = Literal["auto", "pyarrow", "fastparquet"]
+FileWriteMode = Literal[
+    "a", "w", "x", "at", "wt", "xt", "ab", "wb", "xb", "w+", "w+b", "a+", "a+b"
+]
 ColspaceArgType = str | int | Sequence[int | str] | Mapping[Hashable, str | int]
 
 __all__ = ["npt", "type_t"]

pandas-stubs/core/frame.pyi

@@ -1896,55 +1896,6 @@ class DataFrame(NDFrame, OpsMixin):
         self, excel: _bool = ..., sep: _str | None = ..., **kwargs
     ) -> None: ...
     @overload
-    def to_csv(
-        self,
-        path_or_buf: FilePathOrBuffer | None,
-        sep: _str = ...,
-        na_rep: _str = ...,
-        float_format: _str | None = ...,
-        columns: Sequence[Hashable] | None = ...,
-        header: _bool | list[_str] = ...,
-        index: _bool = ...,
-        index_label: _bool | _str | Sequence[Hashable] | None = ...,
-        mode: _str = ...,
-        encoding: _str | None = ...,
-        compression: _str | Mapping[_str, _str] = ...,
-        quoting: int | None = ...,
-        quotechar: _str = ...,
-        line_terminator: _str | None = ...,
-        chunksize: int | None = ...,
-        date_format: _str | None = ...,
-        doublequote: _bool = ...,
-        escapechar: _str | None = ...,
-        decimal: _str = ...,
-        errors: _str = ...,
-        storage_options: dict[_str, Any] | None = ...,
-    ) -> None: ...
-    @overload
-    def to_csv(
-        self,
-        sep: _str = ...,
-        na_rep: _str = ...,
-        float_format: _str | None = ...,
-        columns: Sequence[Hashable] | None = ...,
-        header: _bool | list[_str] = ...,
-        index: _bool = ...,
-        index_label: _bool | _str | Sequence[Hashable] | None = ...,
-        mode: _str = ...,
-        encoding: _str | None = ...,
-        compression: _str | Mapping[_str, _str] = ...,
-        quoting: int | None = ...,
-        quotechar: _str = ...,
-        line_terminator: _str | None = ...,
-        chunksize: int | None = ...,
-        date_format: _str | None = ...,
-        doublequote: _bool = ...,
-        escapechar: _str | None = ...,
-        decimal: _str = ...,
-        errors: _str = ...,
-        storage_options: dict[_str, Any] | None = ...,
-    ) -> _str: ...
-    @overload
     def to_json(
         self,
         path_or_buf: FilePathOrBuffer | None,

pandas-stubs/core/generic.pyi

@@ -22,6 +22,7 @@ from pandas._typing import (
     Dtype,
     FilePath,
     FilePathOrBuffer,
+    FileWriteMode,
     FillnaOptions,
     FrameOrSeries,
     FrameOrSeriesUnion,
@@ -34,6 +35,7 @@ from pandas._typing import (
     Scalar,
     SeriesAxisType,
     SortKind,
+    StorageOptions,
     T,
 )
 
@@ -205,17 +207,17 @@ class NDFrame(PandasObject, indexing.IndexingMixin):
     @overload
     def to_csv(
         self,
-        path_or_buf: FilePathOrBuffer | None,
+        path_or_buf: FilePathOrBuffer,
         sep: _str = ...,
         na_rep: _str = ...,
-        float_format: _str | None = ...,
-        columns: Sequence[Hashable] | None = ...,
+        float_format: _str | Callable | None = ...,
+        columns: list[HashableT] | None = ...,
         header: _bool | list[_str] = ...,
         index: _bool = ...,
-        index_label: _bool | _str | Sequence[Hashable] | None = ...,
-        mode: _str = ...,
+        index_label: Literal[False] | _str | list[HashableT] | None = ...,
+        mode: FileWriteMode = ...,
         encoding: _str | None = ...,
-        compression: _str | Mapping[_str, _str] = ...,
+        compression: CompressionOptions = ...,
         quoting: int | None = ...,
         quotechar: _str = ...,
         line_terminator: _str | None = ...,
@@ -225,21 +227,22 @@ class NDFrame(PandasObject, indexing.IndexingMixin):
         escapechar: _str | None = ...,
         decimal: _str = ...,
         errors: _str = ...,
-        storage_options: dict[_str, Any] | None = ...,
+        storage_options: StorageOptions = ...,
     ) -> None: ...
     @overload
     def to_csv(
         self,
+        path_or_buf: None = ...,
         sep: _str = ...,
         na_rep: _str = ...,
-        float_format: _str | None = ...,
-        columns: Sequence[Hashable] | None = ...,
+        float_format: _str | Callable | None = ...,
+        columns: list[HashableT] | None = ...,
         header: _bool | list[_str] = ...,
         index: _bool = ...,
-        index_label: _bool | _str | Sequence[Hashable] | None = ...,
-        mode: _str = ...,
+        index_label: Literal[False] | _str | list[HashableT] | None = ...,
+        mode: FileWriteMode = ...,
         encoding: _str | None = ...,
-        compression: _str | Mapping[_str, _str] = ...,
+        compression: CompressionOptions = ...,
         quoting: int | None = ...,
         quotechar: _str = ...,
         line_terminator: _str | None = ...,
@@ -249,7 +252,7 @@ class NDFrame(PandasObject, indexing.IndexingMixin):
         escapechar: _str | None = ...,
         decimal: _str = ...,
         errors: _str = ...,
-        storage_options: dict[_str, Any] | None = ...,
+        storage_options: StorageOptions = ...,
     ) -> _str: ...
     def take(
         self, indices, axis=..., is_copy: _bool | None = ..., **kwargs

pandas-stubs/io/common.pyi

@@ -0,0 +1,17 @@
+from typing import (
+    IO,
+    AnyStr,
+    Generic,
+)
+
+from pandas._typing import CompressionDict
+
+class IOHandles(Generic[AnyStr]):
+    handle: IO[AnyStr]
+    compression: CompressionDict
+    created_handles: list[IO[AnyStr]]
+    is_wrapped: bool
+    def close(self) -> None: ...
+    def __enter__(self) -> IOHandles[AnyStr]: ...
+    def __exit__(self, *args: object) -> None: ...
+    def __init__(self, handle, compression, created_handles, is_wrapped) -> None: ...