1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
from __future__ import annotations
from typing import TYPE_CHECKING, Any, Callable, Sequence, TypeVar, cast
from narwhals._compliant.expr import CompliantExpr
from narwhals._compliant.typing import (
CompliantExprAny,
CompliantFrameAny,
CompliantLazyFrameT,
CompliantSeriesOrNativeExprAny,
EagerDataFrameT,
EagerExprT,
EagerSeriesT,
LazyExprAny,
NativeExprT,
WindowFunction,
)
from narwhals._typing_compat import Protocol38
if TYPE_CHECKING:
from typing_extensions import Self, TypeAlias
from narwhals._compliant.typing import EvalSeries, ScalarKwargs
from narwhals._compliant.window import WindowInputs
from narwhals._utils import Implementation, Version, _FullContext
from narwhals.typing import NonNestedLiteral
__all__ = ["CompliantThen", "CompliantWhen", "EagerWhen", "LazyThen", "LazyWhen"]
ExprT = TypeVar("ExprT", bound=CompliantExprAny)
LazyExprT = TypeVar("LazyExprT", bound=LazyExprAny)
SeriesT = TypeVar("SeriesT", bound=CompliantSeriesOrNativeExprAny)
FrameT = TypeVar("FrameT", bound=CompliantFrameAny)
Scalar: TypeAlias = Any
"""A native literal value."""
IntoExpr: TypeAlias = "SeriesT | ExprT | NonNestedLiteral | Scalar"
"""Anything that is convertible into a `CompliantExpr`."""
class CompliantWhen(Protocol38[FrameT, SeriesT, ExprT]):
_condition: ExprT
_then_value: IntoExpr[SeriesT, ExprT]
_otherwise_value: IntoExpr[SeriesT, ExprT] | None
_implementation: Implementation
_backend_version: tuple[int, ...]
_version: Version
@property
def _then(self) -> type[CompliantThen[FrameT, SeriesT, ExprT]]: ...
def __call__(self, compliant_frame: FrameT, /) -> Sequence[SeriesT]: ...
def _window_function(
self, compliant_frame: FrameT, window_inputs: WindowInputs[Any]
) -> Sequence[SeriesT]: ...
def then(
self, value: IntoExpr[SeriesT, ExprT], /
) -> CompliantThen[FrameT, SeriesT, ExprT]:
return self._then.from_when(self, value)
@classmethod
def from_expr(cls, condition: ExprT, /, *, context: _FullContext) -> Self:
obj = cls.__new__(cls)
obj._condition = condition
obj._then_value = None
obj._otherwise_value = None
obj._implementation = context._implementation
obj._backend_version = context._backend_version
obj._version = context._version
return obj
class CompliantThen(CompliantExpr[FrameT, SeriesT], Protocol38[FrameT, SeriesT, ExprT]):
_call: EvalSeries[FrameT, SeriesT]
_when_value: CompliantWhen[FrameT, SeriesT, ExprT]
_function_name: str
_depth: int
_implementation: Implementation
_backend_version: tuple[int, ...]
_version: Version
_scalar_kwargs: ScalarKwargs
@classmethod
def from_when(
cls,
when: CompliantWhen[FrameT, SeriesT, ExprT],
then: IntoExpr[SeriesT, ExprT],
/,
) -> Self:
when._then_value = then
obj = cls.__new__(cls)
obj._call = when
obj._when_value = when
obj._depth = 0
obj._function_name = "whenthen"
obj._evaluate_output_names = getattr(
then, "_evaluate_output_names", lambda _df: ["literal"]
)
obj._alias_output_names = getattr(then, "_alias_output_names", None)
obj._implementation = when._implementation
obj._backend_version = when._backend_version
obj._version = when._version
obj._scalar_kwargs = {}
return obj
def otherwise(self, otherwise: IntoExpr[SeriesT, ExprT], /) -> ExprT:
self._when_value._otherwise_value = otherwise
self._function_name = "whenotherwise"
return cast("ExprT", self)
class LazyThen(
CompliantThen[CompliantLazyFrameT, NativeExprT, LazyExprT],
Protocol38[CompliantLazyFrameT, NativeExprT, LazyExprT],
):
_window_function: WindowFunction[CompliantLazyFrameT, NativeExprT] | None
@classmethod
def from_when(
cls,
when: CompliantWhen[CompliantLazyFrameT, NativeExprT, LazyExprT],
then: IntoExpr[NativeExprT, LazyExprT],
/,
) -> Self:
when._then_value = then
obj = cls.__new__(cls)
obj._call = when
obj._window_function = when._window_function
obj._when_value = when
obj._depth = 0
obj._function_name = "whenthen"
obj._evaluate_output_names = getattr(
then, "_evaluate_output_names", lambda _df: ["literal"]
)
obj._alias_output_names = getattr(then, "_alias_output_names", None)
obj._implementation = when._implementation
obj._backend_version = when._backend_version
obj._version = when._version
obj._scalar_kwargs = {}
return obj
class EagerWhen(
CompliantWhen[EagerDataFrameT, EagerSeriesT, EagerExprT],
Protocol38[EagerDataFrameT, EagerSeriesT, EagerExprT],
):
def _if_then_else(
self, when: EagerSeriesT, then: EagerSeriesT, otherwise: EagerSeriesT | None, /
) -> EagerSeriesT: ...
def __call__(self, df: EagerDataFrameT, /) -> Sequence[EagerSeriesT]:
is_expr = self._condition._is_expr
when: EagerSeriesT = self._condition(df)[0]
then: EagerSeriesT
if is_expr(self._then_value):
then = self._then_value(df)[0]
else:
then = when.alias("literal")._from_scalar(self._then_value)
then._broadcast = True
if is_expr(self._otherwise_value):
otherwise = self._otherwise_value(df)[0]
elif self._otherwise_value is not None:
otherwise = when._from_scalar(self._otherwise_value)
otherwise._broadcast = True
else:
otherwise = self._otherwise_value
return [self._if_then_else(when, then, otherwise)]
class LazyWhen(
CompliantWhen[CompliantLazyFrameT, NativeExprT, LazyExprT],
Protocol38[CompliantLazyFrameT, NativeExprT, LazyExprT],
):
when: Callable[..., NativeExprT]
lit: Callable[..., NativeExprT]
def __call__(self, df: CompliantLazyFrameT) -> Sequence[NativeExprT]:
is_expr = self._condition._is_expr
when = self.when
lit = self.lit
condition = df._evaluate_expr(self._condition)
then_ = self._then_value
then = df._evaluate_expr(then_) if is_expr(then_) else lit(then_)
other_ = self._otherwise_value
if other_ is None:
result = when(condition, then)
else:
otherwise = df._evaluate_expr(other_) if is_expr(other_) else lit(other_)
result = when(condition, then).otherwise(otherwise) # type: ignore # noqa: PGH003
return [result]
@classmethod
def from_expr(cls, condition: LazyExprT, /, *, context: _FullContext) -> Self:
obj = cls.__new__(cls)
obj._condition = condition
obj._then_value = None
obj._otherwise_value = None
obj._implementation = context._implementation
obj._backend_version = context._backend_version
obj._version = context._version
return obj
def _window_function(
self, df: CompliantLazyFrameT, window_inputs: WindowInputs[NativeExprT]
) -> Sequence[NativeExprT]:
is_expr = self._condition._is_expr
condition = self._condition.window_function(df, window_inputs)[0]
then_ = self._then_value
then = (
then_.window_function(df, window_inputs)[0]
if is_expr(then_)
else self.lit(then_)
)
other_ = self._otherwise_value
if other_ is None:
result = self.when(condition, then)
else:
other = (
other_.window_function(df, window_inputs)[0]
if is_expr(other_)
else self.lit(other_)
)
result = self.when(condition, then).otherwise(other) # type: ignore # noqa: PGH003
return [result]
|
