dask_ml.preprocessing.BlockTransformer

class dask_ml.preprocessing.BlockTransformer(func: Callable[..., Union[ArrayLike, pandas.core.frame.DataFrame, dask.dataframe.core.DataFrame]], *, validate: bool = False, **kw_args)

Construct a transformer from a an arbitrary callable

The BlockTransformer forwards the blocks of the X arguments to a user-defined callable and returns the result of this operation. This is useful for stateless operations, that can be performed on the cell or block level, such as taking the log of frequencies. In general the transformer is not suitable for e.g. standardization tasks as this requires information for a complete column.

Parameters:

func : callable

The callable to use for the transformation.

validate : bool, optional default=False

Indicate that the input X array should be checked before calling

func.

kw_args : dict, optional

Dictionary of additional keyword arguments to pass to func.

Examples

>>> import dask.datasets
>>> import pandas as pd
>>> from dask_ml.preprocessing import BlockTransformer
>>> df = dask.datasets.timeseries()
>>> df
... # doctest: +SKIP
Dask DataFrame Structure:
                   id    name        x        y
npartitions=30
2000-01-01      int64  object  float64  float64
2000-01-02        ...     ...      ...      ...
...               ...     ...      ...      ...
2000-01-30        ...     ...      ...      ...
2000-01-31        ...     ...      ...      ...
Dask Name: make-timeseries, 30 tasks
>>> trn = BlockTransformer(pd.util.hash_pandas_object, index=False)
>>> trn.transform(df)
... # doctest: +ELLIPSIS
Dask Series Structure:
npartitions=30
2000-01-01    uint64
2000-01-02       ...
            ...
2000-01-30       ...
2000-01-31       ...
dtype: uint64
Dask Name: hash_pandas_object, 60 tasks

Methods

fit_transform(X[, y])	Fit to data, then transform it.
get_params([deep])	Get parameters for this estimator.
set_params(**params)	Set the parameters of this estimator.

fit
transform

__init__(func: Callable[..., Union[ArrayLike, pandas.core.frame.DataFrame, dask.dataframe.core.DataFrame]], *, validate: bool = False, **kw_args)

Initialize self. See help(type(self)) for accurate signature.

fit_transform(X, y=None, **fit_params)

Fit to data, then transform it.

Fits transformer to X and y with optional parameters fit_params and returns a transformed version of X.

Parameters:

X : {array-like, sparse matrix, dataframe} of shape (n_samples, n_features)

y : ndarray of shape (n_samples,), default=None

Target values.

**fit_params : dict

Additional fit parameters.

Returns:

X_new : ndarray array of shape (n_samples, n_features_new)

Transformed array.

get_params(deep=True)

Get parameters for this estimator.

Parameters:

deep : bool, default=True

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns:

params : mapping of string to any

Parameter names mapped to their values.

set_params(**params)

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as pipelines). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Parameters:

**params : dict

Estimator parameters.

Returns:

self : object

Estimator instance.