cardinal_pythonlib.typing_helpers¶
Original code copyright (C) 2009-2022 Rudolf Cardinal (rudolf@pobox.com).
This file is part of cardinal_pythonlib.
Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Methods and unusual types for type hints.
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class
cardinal_pythonlib.typing_helpers.
CSVWriterType
[source]¶ Type hint for the result of
csv.writer()
See https://stackoverflow.com/questions/51264355/how-to-type-annotate-object-returned-by-csv-writer
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class
cardinal_pythonlib.typing_helpers.
Pep249DatabaseConnectionType
[source]¶ Type hint for a database connection compliant with PEP 249. See https://www.python.org/dev/peps/pep-0249/.
Not supported:
- https://www.python.org/dev/peps/pep-0249/#optional-error-handling-extensions
- https://www.python.org/dev/peps/pep-0249/#optional-two-phase-commit-extensions
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close
() → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#connection-objects
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commit
() → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#connection-objects
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cursor
() → cardinal_pythonlib.typing_helpers.Pep249DatabaseCursorType[source]¶ See https://www.python.org/dev/peps/pep-0249/#connection-objects
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rollback
() → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#connection-objects
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class
cardinal_pythonlib.typing_helpers.
Pep249DatabaseCursorType
(*args, **kwargs)[source]¶ Type hint for a database cursor compliant with PEP 249. See https://www.python.org/dev/peps/pep-0249/#cursor-objects
Example, as per https://docs.python.org/3.6/library/sqlite3.html:
import sqlite3 conn = sqlite3.connect(':memory:') c = conn.cursor() c.execute(''' CREATE TABLE stocks (date text, trans text, symbol text, qty real, price real) ''') c.execute(''' INSERT INTO stocks VALUES ('2006-01-05','BUY','RHAT',100,35.14) ''') conn.commit() c.execute("SELECT * FROM stocks") print(repr(c.description)) help(c)
See also:
-
arraysize
¶ //www.python.org/dev/peps/pep-0249/#cursor-objects
Type: See https
-
callproc
(procname: str, *args, **kwargs) → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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close
() → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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description
¶ A sequence of column_description objects, where each column_description describes one result column and has the following items:
- name:
str
- type_code:
Optional[Type]
? Not sure. - display_size:
Optional[int]
- internal_size:
Optional[int]
- precision:
Optional[int]
- scale:
Optional[int]
- null_ok:
Optional[bool]
The attribute is
None
for operations that don’t return rows, and for un-executed cursors.- name:
-
execute
(operation: str, *args, **kwargs) → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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executemany
(operation: str, *args, **kwargs) → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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fetchall
() → Sequence[Sequence[Any]][source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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fetchmany
(size: int = None) → Sequence[Sequence[Any]][source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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fetchone
() → Optional[Sequence[Any]][source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
-
next
() → Sequence[Any][source]¶ See https://www.python.org/dev/peps/pep-0249/#optional-db-api-extensions
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nextset
() → Optional[bool][source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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rowcount
¶ //www.python.org/dev/peps/pep-0249/#cursor-objects
Type: See https
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scroll
(value: int, mode: str = 'relative') → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#optional-db-api-extensions
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setinputsizes
(sizes: Sequence[Union[Type[CT_co], int]]) → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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setoutputsize
(size: int, column: Optional[int]) → None[source]¶ See https://www.python.org/dev/peps/pep-0249/#cursor-objects
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-
cardinal_pythonlib.typing_helpers.
with_typehint
(baseclass: Type[T]) → Type[T][source]¶ Useful function to make mixins with type hints from a base class.
From https://stackoverflow.com/questions/51930339/how-do-i-correctly-add-type-hints-to-mixin-classes.
Specimen usage:
class MyMixin1(with_typehint(SomeBaseClass))): # ...
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cardinal_pythonlib.typing_helpers.
with_typehints
(*baseclasses) → Type[T][source]¶ Useful function to make mixins with type hints from multiple base classes.
From https://stackoverflow.com/questions/51930339/how-do-i-correctly-add-type-hints-to-mixin-classes.
Specimen usage:
class MyMixin2(*with_typehints(SomeBaseClass, AnotherBaseClass))): # ...