kedro_datasets.polars.CSVDataSet¶

class kedro_datasets.polars.CSVDataSet(filepath, load_args=None, save_args=None, version=None, credentials=None, fs_args=None, metadata=None)[source]¶

CSVDataSet loads/saves data from/to a CSV file using an underlying filesystem (e.g.: local, S3, GCS). It uses polars to handle the CSV file.

Example adding a catalog entry with YAML API:

cars:
  type: polars.CSVDataSet
  filepath: data/01_raw/company/cars.csv
  load_args:
    sep: ","
    parse_dates: False
  save_args:
    has_header: False
       null_value: "somenullstring"

motorbikes:
  type: polars.CSVDataSet
  filepath: s3://your_bucket/data/02_intermediate/company/motorbikes.csv
  credentials: dev_s3

Example using Python API:

from kedro_datasets.polars import CSVDataSet
import polars as pl

data = pl.DataFrame({'col1': [1, 2], 'col2': [4, 5],
                     'col3': [5, 6]})

data_set = CSVDataSet(filepath="test.csv")
data_set.save(data)
reloaded = data_set.load()
assert data.frame_equal(reloaded)

Attributes

`DEFAULT_LOAD_ARGS`
`DEFAULT_SAVE_ARGS`

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.
`resolve_load_version`()	Compute the version the dataset should be loaded with.
`resolve_save_version`()	Compute the version the dataset should be saved with.
`save`(data)	Saves data by delegation to the provided save method.

DEFAULT_LOAD_ARGS: Dict[str, Any] = {'rechunk': True}¶

DEFAULT_SAVE_ARGS: Dict[str, Any] = {}¶

__init__(filepath, load_args=None, save_args=None, version=None, credentials=None, fs_args=None, metadata=None)[source]¶

Creates a new instance of CSVDataSet pointing to a concrete CSV file on a specific filesystem.

Parameters

filepath (str) – Filepath in POSIX format to a CSV file prefixed with a protocol s3://. If prefix is not provided, file protocol (local filesystem) will be used. The prefix should be any protocol supported by fsspec. Note: http(s) doesn’t support versioning.
load_args (Optional[Dict[str, Any]]) – Polars options for loading CSV files. Here you can find all available arguments: https://pola-rs.github.io/polars/py-polars/html/reference/api/polars.read_csv.html#polars.read_csv All defaults are preserved, but we explicity use rechunk=True for seaborn compability.
save_args (Optional[Dict[str, Any]]) – Polars options for saving CSV files. Here you can find all available arguments: https://pola-rs.github.io/polars/py-polars/html/reference/api/polars.DataFrame.write_csv.html All defaults are preserved.
version (Optional[Version]) – If specified, should be an instance of kedro.io.core.Version. If its load attribute is None, the latest version will be loaded. If its save attribute is None, save version will be autogenerated.
credentials (Optional[Dict[str, Any]]) – Credentials required to get access to the underlying filesystem. E.g. for GCSFileSystem it should look like {“token”: None}.
fs_args (Optional[Dict[str, Any]]) – Extra arguments to pass into underlying filesystem class constructor (e.g. {“project”: “my-project”} for GCSFileSystem).
metadata (Optional[Dict[str, Any]]) – Any arbitrary metadata. This is ignored by Kedro, but may be consumed by users or external plugins.

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 – Data set name.
config – Data set config dictionary.
load_version – Version string to be used for load operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.
save_version – Version string to be used for save operation if the data set is versioned. Has no effect on the data set if versioning was not enabled.

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: TypeVar(_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

resolve_load_version()¶

Compute the version the dataset should be loaded with.

Return type: str | None

resolve_save_version()¶

Compute the version the dataset should be saved with.

Return type: str | None

save(data)¶

Saves data by delegation to the provided save method.

Parameters

data (TypeVar(_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