TYP: read_csv's usecols (pandas-dev#55330)

* TYP: read_csv's usecols * adjust doc * use range
jbrockmendel · Oct 4, 2023 · da01e38 · da01e38
1 parent 6a83910
commit da01e38
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 42 deletions.
diff --git a/pandas/_typing.py b/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,
+]
diff --git a/pandas/io/parsers/readers.py b/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,