PERF: dtype checks (#52279)

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>

pandas/_testing/asserters.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from typing import (
+    TYPE_CHECKING,
     Literal,
     cast,
 )
@@ -21,6 +22,7 @@
 )
 from pandas.core.dtypes.dtypes import (
     CategoricalDtype,
+    ExtensionDtype,
     PandasDtype,
 )
 from pandas.core.dtypes.missing import array_equivalent
@@ -53,6 +55,9 @@
 
 from pandas.io.formats.printing import pprint_thing
 
+if TYPE_CHECKING:
+    from pandas._typing import DtypeObj
+
 
 def assert_almost_equal(
     left,
@@ -965,7 +970,9 @@ def assert_series_equal(
             obj=str(obj),
             index_values=np.asarray(left.index),
         )
-    elif is_extension_array_dtype(left.dtype) and is_extension_array_dtype(right.dtype):
+    elif isinstance(left.dtype, ExtensionDtype) and isinstance(
+        right.dtype, ExtensionDtype
+    ):
         assert_extension_array_equal(
             left._values,
             right._values,
@@ -1320,7 +1327,9 @@ def assert_copy(iter1, iter2, **eql_kwargs) -> None:
         assert elem1 is not elem2, msg
 
 
-def is_extension_array_dtype_and_needs_i8_conversion(left_dtype, right_dtype) -> bool:
+def is_extension_array_dtype_and_needs_i8_conversion(
+    left_dtype: DtypeObj, right_dtype: DtypeObj
+) -> bool:
     """
     Checks that we have the combination of an ExtensionArraydtype and
     a dtype that should be converted to int64
@@ -1331,7 +1340,7 @@ def is_extension_array_dtype_and_needs_i8_conversion(left_dtype, right_dtype) ->
 
     Related to issue #37609
     """
-    return is_extension_array_dtype(left_dtype) and needs_i8_conversion(right_dtype)
+    return isinstance(left_dtype, ExtensionDtype) and needs_i8_conversion(right_dtype)
 
 
 def assert_indexing_slices_equivalent(ser: Series, l_slc: slice, i_slc: slice) -> None:

pandas/core/apply.py

@@ -40,10 +40,10 @@
 from pandas.core.dtypes.cast import is_nested_object
 from pandas.core.dtypes.common import (
     is_dict_like,
-    is_extension_array_dtype,
     is_list_like,
     is_sequence,
 )
+from pandas.core.dtypes.dtypes import ExtensionDtype
 from pandas.core.dtypes.generic import (
     ABCDataFrame,
     ABCNDFrame,
@@ -940,7 +940,7 @@ def series_generator(self):
         ser = self.obj._ixs(0, axis=0)
         mgr = ser._mgr
 
-        if is_extension_array_dtype(ser.dtype):
+        if isinstance(ser.dtype, ExtensionDtype):
             # values will be incorrect for this block
             # TODO(EA2D): special case would be unnecessary with 2D EAs
             obj = self.obj

pandas/core/arrays/categorical.py

@@ -437,7 +437,7 @@ def __init__(
             # we're inferring from values
             dtype = CategoricalDtype(categories, dtype.ordered)
 
-        elif is_categorical_dtype(values.dtype):
+        elif isinstance(values.dtype, CategoricalDtype):
             old_codes = extract_array(values)._codes
             codes = recode_for_categories(
                 old_codes, values.dtype.categories, dtype.categories, copy=copy
@@ -504,9 +504,7 @@ def astype(self, dtype: AstypeArg, copy: bool = True) -> ArrayLike:
         if self.dtype is dtype:
             result = self.copy() if copy else self
 
-        elif is_categorical_dtype(dtype):
-            dtype = cast(CategoricalDtype, dtype)
-
+        elif isinstance(dtype, CategoricalDtype):
             # GH 10696/18593/18630
             dtype = self.dtype.update_dtype(dtype)
             self = self.copy() if copy else self
@@ -2497,7 +2495,7 @@ def __init__(self, data) -> None:
 
     @staticmethod
     def _validate(data):
-        if not is_categorical_dtype(data.dtype):
+        if not isinstance(data.dtype, CategoricalDtype):
             raise AttributeError("Can only use .cat accessor with a 'category' dtype")
 
     # error: Signature of "_delegate_property_get" incompatible with supertype

pandas/core/arrays/datetimelike.py

@@ -91,7 +91,6 @@
     is_integer_dtype,
     is_list_like,
     is_object_dtype,
-    is_period_dtype,
     is_string_dtype,
     is_timedelta64_dtype,
     pandas_dtype,
@@ -1405,7 +1404,7 @@ def __sub__(self, other):
         ):
             # DatetimeIndex, ndarray[datetime64]
             result = self._sub_datetime_arraylike(other)
-        elif is_period_dtype(other_dtype):
+        elif isinstance(other_dtype, PeriodDtype):
             # PeriodIndex
             result = self._sub_periodlike(other)
         elif is_integer_dtype(other_dtype):

pandas/core/arrays/interval.py

@@ -12,7 +12,6 @@
     Literal,
     Sequence,
     Union,
-    cast,
     overload,
 )
 
@@ -55,15 +54,17 @@
     is_dtype_equal,
     is_float_dtype,
     is_integer_dtype,
-    is_interval_dtype,
     is_list_like,
     is_object_dtype,
     is_scalar,
     is_string_dtype,
     needs_i8_conversion,
     pandas_dtype,
 )
-from pandas.core.dtypes.dtypes import IntervalDtype
+from pandas.core.dtypes.dtypes import (
+    CategoricalDtype,
+    IntervalDtype,
+)
 from pandas.core.dtypes.generic import (
     ABCDataFrame,
     ABCDatetimeIndex,
@@ -317,8 +318,7 @@ def _ensure_simple_new_inputs(
         if dtype is not None:
             # GH 19262: dtype must be an IntervalDtype to override inferred
             dtype = pandas_dtype(dtype)
-            if is_interval_dtype(dtype):
-                dtype = cast(IntervalDtype, dtype)
+            if isinstance(dtype, IntervalDtype):
                 if dtype.subtype is not None:
                     left = left.astype(dtype.subtype)
                     right = right.astype(dtype.subtype)
@@ -344,7 +344,7 @@ def _ensure_simple_new_inputs(
                 f"right [{type(right).__name__}] types"
             )
             raise ValueError(msg)
-        if is_categorical_dtype(left.dtype) or is_string_dtype(left.dtype):
+        if isinstance(left.dtype, CategoricalDtype) or is_string_dtype(left.dtype):
             # GH 19016
             msg = (
                 "category, object, and string subtypes are not supported "
@@ -752,14 +752,14 @@ def _cmp_method(self, other, op):
         # determine the dtype of the elements we want to compare
         if isinstance(other, Interval):
             other_dtype = pandas_dtype("interval")
-        elif not is_categorical_dtype(other.dtype):
+        elif not isinstance(other.dtype, CategoricalDtype):
             other_dtype = other.dtype
         else:
             # for categorical defer to categories for dtype
             other_dtype = other.categories.dtype
 
             # extract intervals if we have interval categories with matching closed
-            if is_interval_dtype(other_dtype):
+            if isinstance(other_dtype, IntervalDtype):
                 if self.closed != other.categories.closed:
                     return invalid_comparison(self, other, op)
 
@@ -768,7 +768,7 @@ def _cmp_method(self, other, op):
                 )
 
         # interval-like -> need same closed and matching endpoints
-        if is_interval_dtype(other_dtype):
+        if isinstance(other_dtype, IntervalDtype):
             if self.closed != other.closed:
                 return invalid_comparison(self, other, op)
             elif not isinstance(other, Interval):
@@ -951,7 +951,7 @@ def astype(self, dtype, copy: bool = True):
         if dtype is not None:
             dtype = pandas_dtype(dtype)
 
-        if is_interval_dtype(dtype):
+        if isinstance(dtype, IntervalDtype):
             if dtype == self.dtype:
                 return self.copy() if copy else self
 
@@ -1683,7 +1683,7 @@ def isin(self, values) -> npt.NDArray[np.bool_]:
             values = np.array(values)
         values = extract_array(values, extract_numpy=True)
 
-        if is_interval_dtype(values.dtype):
+        if isinstance(values.dtype, IntervalDtype):
             if self.closed != values.closed:
                 # not comparable -> no overlap
                 return np.zeros(self.shape, dtype=bool)

pandas/core/arrays/period.py

@@ -635,7 +635,7 @@ def astype(self, dtype, copy: bool = True):
                 return self
             else:
                 return self.copy()
-        if is_period_dtype(dtype):
+        if isinstance(dtype, PeriodDtype):
             return self.asfreq(dtype.freq)
 
         if is_datetime64_any_dtype(dtype):
@@ -897,7 +897,7 @@ def period_array(
 
     if is_datetime64_dtype(data_dtype):
         return PeriodArray._from_datetime64(data, freq)
-    if is_period_dtype(data_dtype):
+    if isinstance(data_dtype, PeriodDtype):
         return PeriodArray(data, freq=freq)
 
     # other iterable of some kind
@@ -966,7 +966,7 @@ def validate_dtype_freq(
 
     if dtype is not None:
         dtype = pandas_dtype(dtype)
-        if not is_period_dtype(dtype):
+        if not isinstance(dtype, PeriodDtype):
             raise ValueError("dtype must be PeriodDtype")
         if freq is None:
             freq = dtype.freq

pandas/core/arrays/sparse/array.py

@@ -45,7 +45,6 @@
     is_array_like,
     is_bool_dtype,
     is_datetime64_any_dtype,
-    is_datetime64tz_dtype,
     is_dtype_equal,
     is_integer,
     is_list_like,
@@ -54,6 +53,7 @@
     is_string_dtype,
     pandas_dtype,
 )
+from pandas.core.dtypes.dtypes import DatetimeTZDtype
 from pandas.core.dtypes.generic import (
     ABCIndex,
     ABCSeries,
@@ -458,7 +458,7 @@ def __init__(
             data = extract_array(data, extract_numpy=True)
             if not isinstance(data, np.ndarray):
                 # EA
-                if is_datetime64tz_dtype(data.dtype):
+                if isinstance(data.dtype, DatetimeTZDtype):
                     warnings.warn(
                         f"Creating SparseArray from {data.dtype} data "
                         "loses timezone information. Cast to object before "

pandas/core/base.py

@@ -42,10 +42,10 @@
 
 from pandas.core.dtypes.cast import can_hold_element
 from pandas.core.dtypes.common import (
-    is_extension_array_dtype,
     is_object_dtype,
     is_scalar,
 )
+from pandas.core.dtypes.dtypes import ExtensionDtype
 from pandas.core.dtypes.generic import (
     ABCDataFrame,
     ABCIndex,
@@ -565,7 +565,7 @@ def to_numpy(
         array(['1999-12-31T23:00:00.000000000', '2000-01-01T23:00:00...'],
               dtype='datetime64[ns]')
         """
-        if is_extension_array_dtype(self.dtype):
+        if isinstance(self.dtype, ExtensionDtype):
             return self.array.to_numpy(dtype, copy=copy, na_value=na_value, **kwargs)
         elif kwargs:
             bad_keys = list(kwargs.keys())[0]
@@ -1132,7 +1132,7 @@ def _memory_usage(self, deep: bool = False) -> int:
             )
 
         v = self.array.nbytes
-        if deep and is_object_dtype(self) and not PYPY:
+        if deep and is_object_dtype(self.dtype) and not PYPY:
             values = cast(np.ndarray, self._values)
             v += lib.memory_usage_of_objects(values)
         return v

pandas/core/common.py

@@ -35,9 +35,9 @@
 from pandas.core.dtypes.common import (
     is_array_like,
     is_bool_dtype,
-    is_extension_array_dtype,
     is_integer,
 )
+from pandas.core.dtypes.dtypes import ExtensionDtype
 from pandas.core.dtypes.generic import (
     ABCExtensionArray,
     ABCIndex,
@@ -122,7 +122,7 @@ def is_bool_indexer(key: Any) -> bool:
         and convert to an ndarray.
     """
     if isinstance(key, (ABCSeries, np.ndarray, ABCIndex)) or (
-        is_array_like(key) and is_extension_array_dtype(key.dtype)
+        is_array_like(key) and isinstance(key.dtype, ExtensionDtype)
     ):
         if key.dtype == np.object_:
             key_array = np.asarray(key)

pandas/core/generic.py

@@ -110,7 +110,6 @@
     is_bool,
     is_bool_dtype,
     is_datetime64_any_dtype,
-    is_datetime64tz_dtype,
     is_dict_like,
     is_dtype_equal,
     is_extension_array_dtype,
@@ -123,6 +122,7 @@
     is_timedelta64_dtype,
     pandas_dtype,
 )
+from pandas.core.dtypes.dtypes import DatetimeTZDtype
 from pandas.core.dtypes.generic import (
     ABCDataFrame,
     ABCSeries,
@@ -9623,7 +9623,7 @@ def align(
         if self.ndim == 1 or axis == 0:
             # If we are aligning timezone-aware DatetimeIndexes and the timezones
             #  do not match, convert both to UTC.
-            if is_datetime64tz_dtype(left.index.dtype):
+            if isinstance(left.index.dtype, DatetimeTZDtype):
                 if left.index.tz != right.index.tz:
                     if join_index is not None:
                         # GH#33671 copy to ensure we don't change the index on

pandas/core/groupby/generic.py

@@ -43,13 +43,15 @@
 from pandas.core.dtypes.common import (
     ensure_int64,
     is_bool,
-    is_categorical_dtype,
     is_dict_like,
     is_integer_dtype,
-    is_interval_dtype,
     is_numeric_dtype,
     is_scalar,
 )
+from pandas.core.dtypes.dtypes import (
+    CategoricalDtype,
+    IntervalDtype,
+)
 from pandas.core.dtypes.missing import (
     isna,
     notna,
@@ -681,7 +683,7 @@ def value_counts(
 
         index_names = self.grouper.names + [self.obj.name]
 
-        if is_categorical_dtype(val.dtype) or (
+        if isinstance(val.dtype, CategoricalDtype) or (
             bins is not None and not np.iterable(bins)
         ):
             # scalar bins cannot be done at top level
@@ -717,7 +719,7 @@ def value_counts(
             )
             llab = lambda lab, inc: lab[inc]._multiindex.codes[-1]
 
-        if is_interval_dtype(lab.dtype):
+        if isinstance(lab.dtype, IntervalDtype):
             # TODO: should we do this inside II?
             lab_interval = cast(Interval, lab)