kedro.io.LambdaDataSet¶
-
class
kedro.io.
LambdaDataSet
(load, save, exists=None, release=None)[source]¶ LambdaDataSet
loads and saves data to a data set. It relies on delegating to specific implementation such as csv, sql, etc.LambdaDataSet
class captures Exceptions while performing operations on composedDataSet
implementations. The composed data set is responsible for providing information on how to resolve the issue when possible. This information should be available through str(error).Example:
from kedro.io import LambdaDataSet import pandas as pd file_name = "test.csv" def load() -> pd.DataFrame: raise FileNotFoundError("'{}' csv file not found." .format(file_name)) data_set = LambdaDataSet(load, None)
Methods
exists
()Checks whether a data set’s output already exists by calling the provided _exists() method.
from_config
(name, config[, load_version, …])Create a data set instance using the configuration provided.
load
()Loads data by delegation to the provided load method.
release
()Release any cached data.
save
(data)Saves data by delegation to the provided save method.
-
__init__
(load, save, exists=None, release=None)[source]¶ Creates a new instance of
LambdaDataSet
with references to the required input/output data set methods.- Parameters
load (
Optional
[Callable
[[],Any
]]) – Method to load data from a data set.save (
Optional
[Callable
[[Any
],None
]]) – Method to save data to a data set.exists (
Optional
[Callable
[[],bool
]]) – Method to check whether output data already exists.release (
Optional
[Callable
[[],None
]]) – Method to release any cached information.
- Raises
DataSetError – If a method is specified, but is not a Callable.
-
exists
()¶ Checks whether a data set’s output already exists by calling the provided _exists() method.
- Return type
bool
- Returns
Flag indicating whether the output already exists.
- Raises
DataSetError – when underlying exists method raises error.
-
classmethod
from_config
(name, config, load_version=None, save_version=None)¶ Create a data set instance using the configuration provided.
- Parameters
name (
str
) – Data set name.config (
Dict
[str
,Any
]) – Data set config dictionary.load_version (
Optional
[str
]) – Version string to be used forload
operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.save_version (
Optional
[str
]) – Version string to be used forsave
operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.
- Return type
AbstractDataSet
- Returns
An instance of an
AbstractDataSet
subclass.- Raises
DataSetError – When the function fails to create the data set from its config.
-
load
()¶ Loads data by delegation to the provided load method.
- Return type
~_DO
- Returns
Data returned by the provided load method.
- Raises
DataSetError – When underlying load method raises error.
-
release
()¶ Release any cached data.
- Raises
DataSetError – when underlying release method raises error.
- Return type
None
-
save
(data)¶ Saves data by delegation to the provided save method.
- Parameters
data (~_DI) – the value to be saved by provided save method.
- Raises
DataSetError – when underlying save method raises error.
FileNotFoundError – when save method got file instead of dir, on Windows.
NotADirectoryError – when save method got file instead of dir, on Unix.
- Return type
None
-