TYP: use from __future__ import annotations more

Author: simonjayhawkins

pandas/io/json/_json.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from abc import (
     ABC,
     abstractmethod,
@@ -10,10 +12,6 @@
     Any,
     Callable,
     Mapping,
-    Optional,
-    Tuple,
-    Type,
-    Union,
 )
 
 import numpy as np
@@ -78,12 +76,12 @@
 def to_json(
     path_or_buf,
     obj: NDFrame,
-    orient: Optional[str] = None,
+    orient: str | None = None,
     date_format: str = "epoch",
     double_precision: int = 10,
     force_ascii: bool = True,
     date_unit: str = "ms",
-    default_handler: Optional[Callable[[Any], JSONSerializable]] = None,
+    default_handler: Callable[[Any], JSONSerializable] | None = None,
     lines: bool = False,
     compression: CompressionOptions = "infer",
     index: bool = True,
@@ -102,7 +100,7 @@ def to_json(
     if orient == "table" and isinstance(obj, Series):
         obj = obj.to_frame(name=obj.name or "values")
 
-    writer: Type[Writer]
+    writer: type[Writer]
     if orient == "table" and isinstance(obj, DataFrame):
         writer = JSONTableWriter
     elif isinstance(obj, Series):
@@ -143,13 +141,13 @@ class Writer(ABC):
     def __init__(
         self,
         obj,
-        orient: Optional[str],
+        orient: str | None,
         date_format: str,
         double_precision: int,
         ensure_ascii: bool,
         date_unit: str,
         index: bool,
-        default_handler: Optional[Callable[[Any], JSONSerializable]] = None,
+        default_handler: Callable[[Any], JSONSerializable] | None = None,
         indent: int = 0,
     ):
         self.obj = obj
@@ -187,7 +185,7 @@ def write(self):
 
     @property
     @abstractmethod
-    def obj_to_write(self) -> Union[NDFrame, Mapping[IndexLabel, Any]]:
+    def obj_to_write(self) -> NDFrame | Mapping[IndexLabel, Any]:
         """Object to write in JSON format."""
         pass
 
@@ -196,7 +194,7 @@ class SeriesWriter(Writer):
     _default_orient = "index"
 
     @property
-    def obj_to_write(self) -> Union[NDFrame, Mapping[IndexLabel, Any]]:
+    def obj_to_write(self) -> NDFrame | Mapping[IndexLabel, Any]:
         if not self.index and self.orient == "split":
             return {"name": self.obj.name, "data": self.obj.values}
         else:
@@ -211,7 +209,7 @@ class FrameWriter(Writer):
     _default_orient = "columns"
 
     @property
-    def obj_to_write(self) -> Union[NDFrame, Mapping[IndexLabel, Any]]:
+    def obj_to_write(self) -> NDFrame | Mapping[IndexLabel, Any]:
         if not self.index and self.orient == "split":
             obj_to_write = self.obj.to_dict(orient="split")
             del obj_to_write["index"]
@@ -243,13 +241,13 @@ class JSONTableWriter(FrameWriter):
     def __init__(
         self,
         obj,
-        orient: Optional[str],
+        orient: str | None,
         date_format: str,
         double_precision: int,
         ensure_ascii: bool,
         date_unit: str,
         index: bool,
-        default_handler: Optional[Callable[[Any], JSONSerializable]] = None,
+        default_handler: Callable[[Any], JSONSerializable] | None = None,
         indent: int = 0,
     ):
         """
@@ -313,7 +311,7 @@ def __init__(
         self.index = index
 
     @property
-    def obj_to_write(self) -> Union[NDFrame, Mapping[IndexLabel, Any]]:
+    def obj_to_write(self) -> NDFrame | Mapping[IndexLabel, Any]:
         return {"schema": self.schema, "data": self.obj}
 
 
@@ -326,19 +324,19 @@ def read_json(
     path_or_buf=None,
     orient=None,
     typ="frame",
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
     convert_axes=None,
     convert_dates=True,
     keep_default_dates: bool = True,
     numpy: bool = False,
     precise_float: bool = False,
     date_unit=None,
     encoding=None,
-    encoding_errors: Optional[str] = "strict",
+    encoding_errors: str | None = "strict",
     lines: bool = False,
-    chunksize: Optional[int] = None,
+    chunksize: int | None = None,
     compression: CompressionOptions = "infer",
-    nrows: Optional[int] = None,
+    nrows: int | None = None,
     storage_options: StorageOptions = None,
 ):
     """
@@ -639,11 +637,11 @@ def __init__(
         date_unit,
         encoding,
         lines: bool,
-        chunksize: Optional[int],
+        chunksize: int | None,
         compression: CompressionOptions,
-        nrows: Optional[int],
+        nrows: int | None,
         storage_options: StorageOptions = None,
-        encoding_errors: Optional[str] = "strict",
+        encoding_errors: str | None = "strict",
     ):
 
         self.orient = orient
@@ -663,7 +661,7 @@ def __init__(
         self.nrows_seen = 0
         self.nrows = nrows
         self.encoding_errors = encoding_errors
-        self.handles: Optional[IOHandles] = None
+        self.handles: IOHandles | None = None
 
         if self.chunksize is not None:
             self.chunksize = validate_integer("chunksize", self.chunksize, 1)
@@ -816,7 +814,7 @@ def __exit__(self, exc_type, exc_value, traceback):
 
 
 class Parser:
-    _split_keys: Tuple[str, ...]
+    _split_keys: tuple[str, ...]
     _default_orient: str
 
     _STAMP_UNITS = ("s", "ms", "us", "ns")
@@ -831,7 +829,7 @@ def __init__(
         self,
         json,
         orient,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
         convert_axes=True,
         convert_dates=True,
         keep_default_dates=False,
@@ -865,7 +863,7 @@ def __init__(
         self.convert_dates = convert_dates
         self.date_unit = date_unit
         self.keep_default_dates = keep_default_dates
-        self.obj: Optional[FrameOrSeriesUnion] = None
+        self.obj: FrameOrSeriesUnion | None = None
 
     def check_keys_split(self, decoded):
         """

pandas/io/parsers/readers.py

@@ -1,18 +1,13 @@
 """
 Module contains tools for processing files into DataFrames or other objects
 """
+from __future__ import annotations
+
 from collections import abc
 import csv
 import sys
 from textwrap import fill
-from typing import (
-    Any,
-    Dict,
-    List,
-    Optional,
-    Set,
-    Type,
-)
+from typing import Any
 import warnings
 
 import numpy as np
@@ -413,8 +408,8 @@
 _c_unsupported = {"skipfooter"}
 _python_unsupported = {"low_memory", "float_precision"}
 
-_deprecated_defaults: Dict[str, Any] = {"error_bad_lines": None, "warn_bad_lines": None}
-_deprecated_args: Set[str] = {"error_bad_lines", "warn_bad_lines"}
+_deprecated_defaults: dict[str, Any] = {"error_bad_lines": None, "warn_bad_lines": None}
+_deprecated_args: set[str] = {"error_bad_lines", "warn_bad_lines"}
 
 
 def validate_integer(name, val, min_val=0):
@@ -518,7 +513,7 @@ def read_csv(
     prefix=lib.no_default,
     mangle_dupe_cols=True,
     # General Parsing Configuration
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
     engine=None,
     converters=None,
     true_values=None,
@@ -554,7 +549,7 @@ def read_csv(
     escapechar=None,
     comment=None,
     encoding=None,
-    encoding_errors: Optional[str] = "strict",
+    encoding_errors: str | None = "strict",
     dialect=None,
     # Error Handling
     error_bad_lines=None,
@@ -616,7 +611,7 @@ def read_table(
     prefix=lib.no_default,
     mangle_dupe_cols=True,
     # General Parsing Configuration
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
     engine=None,
     converters=None,
     true_values=None,
@@ -659,7 +654,7 @@ def read_table(
     # TODO (2.0): set on_bad_lines to "error".
     # See _refine_defaults_read comment for why we do this.
     on_bad_lines=None,
-    encoding_errors: Optional[str] = "strict",
+    encoding_errors: str | None = "strict",
     # Internal
     delim_whitespace=False,
     low_memory=_c_parser_defaults["low_memory"],
@@ -823,7 +818,7 @@ def _get_options_with_defaults(self, engine):
         kwds = self.orig_options
 
         options = {}
-        default: Optional[object]
+        default: object | None
 
         for argname, default in parser_defaults.items():
             value = kwds.get(argname, default)
@@ -1033,7 +1028,7 @@ def __next__(self):
             raise
 
     def _make_engine(self, engine="c"):
-        mapping: Dict[str, Type[ParserBase]] = {
+        mapping: dict[str, type[ParserBase]] = {
             "c": CParserWrapper,
             "python": PythonParser,
             "python-fwf": FixedWidthFieldParser,
@@ -1147,7 +1142,7 @@ def TextParser(*args, **kwds):
 
 
 def _clean_na_values(na_values, keep_default_na=True):
-    na_fvalues: Union[Set, Dict]
+    na_fvalues: Union[set, dict]
     if na_values is None:
         if keep_default_na:
             na_values = STR_NA_VALUES
@@ -1198,7 +1193,7 @@ def _floatify_na_values(na_values):
 
 def _stringify_na_values(na_values):
     """ return a stringified and numeric for these values """
-    result: List[Union[int, str, float]] = []
+    result: list[Union[int, str, float]] = []
     for x in na_values:
         result.append(str(x))
         result.append(x)
@@ -1227,12 +1222,12 @@ def _refine_defaults_read(
     delim_whitespace: bool,
     engine: str,
     sep: Union[str, object],
-    error_bad_lines: Optional[bool],
-    warn_bad_lines: Optional[bool],
-    on_bad_lines: Optional[str],
-    names: Union[Optional[ArrayLike], object],
-    prefix: Union[Optional[str], object],
-    defaults: Dict[str, Any],
+    error_bad_lines: bool | None,
+    warn_bad_lines: bool | None,
+    on_bad_lines: str | None,
+    names: Union[ArrayLike | None, object],
+    prefix: Union[str | None, object],
+    defaults: dict[str, Any],
 ):
     """Validate/refine default values of input parameters of read_csv, read_table.
 
@@ -1287,7 +1282,7 @@ def _refine_defaults_read(
     """
     # fix types for sep, delimiter to Union(str, Any)
     delim_default = defaults["delimiter"]
-    kwds: Dict[str, Any] = {}
+    kwds: dict[str, Any] = {}
     # gh-23761
     #
     # When a dialect is passed, it overrides any of the overlapping
@@ -1381,7 +1376,7 @@ def _refine_defaults_read(
     return kwds
 
 
-def _extract_dialect(kwds: Dict[str, Any]) -> Optional[csv.Dialect]:
+def _extract_dialect(kwds: dict[str, Any]) -> csv.Dialect | None:
     """
     Extract concrete csv dialect instance.
 
@@ -1427,8 +1422,8 @@ def _validate_dialect(dialect: csv.Dialect) -> None:
 
 def _merge_with_dialect_properties(
     dialect: csv.Dialect,
-    defaults: Dict[str, Any],
-) -> Dict[str, Any]:
+    defaults: dict[str, Any],
+) -> dict[str, Any]:
     """
     Merge default kwargs in TextFileReader with dialect parameters.
 
@@ -1477,7 +1472,7 @@ def _merge_with_dialect_properties(
     return kwds
 
 
-def _validate_skipfooter(kwds: Dict[str, Any]) -> None:
+def _validate_skipfooter(kwds: dict[str, Any]) -> None:
     """
     Check whether skipfooter is compatible with other kwargs in TextFileReader.