TYP: read_csv's usecols (#55330)

* TYP: read_csv's usecols * adjust doc * use range

Author: twoertwein

pandas/_typing.py

@@ -509,3 +509,12 @@ def closed(self) -> bool:
 
 # Offsets
 OffsetCalendar = Union[np.busdaycalendar, "AbstractHolidayCalendar"]
+
+# read_csv: usecols
+UsecolsArgType = Union[
+ SequenceNotStr[Hashable],
+ range,
+ AnyArrayLike,
+ Callable[[HashableT], bool],
+ None,
+]

pandas/io/parsers/readers.py

@@ -77,11 +77,11 @@
  DtypeArg,
  DtypeBackend,
  FilePath,
- HashableT,
  IndexLabel,
  ReadCsvBuffer,
  Self,
  StorageOptions,
+ UsecolsArgType,
  )
 _doc_read_csv_and_table = (
  r"""
@@ -142,7 +142,7 @@
  Note: ``index_col=False`` can be used to force pandas to *not* use the first
  column as the index, e.g., when you have a malformed file with delimiters at
  the end of each line.
-usecols : list of Hashable or Callable, optional
+usecols : Sequence of Hashable or Callable, optional
  Subset of columns to select, denoted either by column labels or column indices.
  If list-like, all elements must either
  be positional (i.e. integer indices into the document columns) or strings
@@ -645,10 +645,7 @@ def read_csv(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -707,10 +704,7 @@ def read_csv(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -770,10 +764,7 @@ def read_csv(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -833,10 +824,7 @@ def read_csv(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -907,10 +895,7 @@ def read_csv(
  header: int | Sequence[int] | None | Literal["infer"] = "infer",
  names: Sequence[Hashable] | None | lib.NoDefault = lib.no_default,
  index_col: IndexLabel | Literal[False] | None = None,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = None,
+ usecols: UsecolsArgType = None,
  # General Parsing Configuration
  dtype: DtypeArg | None = None,
  engine: CSVEngine | None = None,
@@ -1005,10 +990,7 @@ def read_table(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -1065,10 +1047,7 @@ def read_table(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -1125,10 +1104,7 @@ def read_table(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -1185,10 +1161,7 @@ def read_table(
  header: int | Sequence[int] | None | Literal["infer"] = ...,
  names: Sequence[Hashable] | None | lib.NoDefault = ...,
  index_col: IndexLabel | Literal[False] | None = ...,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = ...,
+ usecols: UsecolsArgType = ...,
  dtype: DtypeArg | None = ...,
  engine: CSVEngine | None = ...,
  converters: Mapping[Hashable, Callable] | None = ...,
@@ -1258,10 +1231,7 @@ def read_table(
  header: int | Sequence[int] | None | Literal["infer"] = "infer",
  names: Sequence[Hashable] | None | lib.NoDefault = lib.no_default,
  index_col: IndexLabel | Literal[False] | None = None,
- usecols: list[HashableT]
- | tuple[HashableT]
- | Callable[[Hashable], bool]
- | None = None,
+ usecols: UsecolsArgType = None,
  # General Parsing Configuration
  dtype: DtypeArg | None = None,
  engine: CSVEngine | None = None,