gators.data_cleaning.DropLowCardinality

class gators.data_cleaning.DropLowCardinality(min_categories: int)[source]

Drop the categorical columns having a low cardinality.

Parameters
min_categoriesint

Min categories allowed.

Examples

Imports and initialization:

>>> from gators.data_cleaning import DropLowCardinality
>>> obj = DropLowCardinality(min_categories=2)

The fit, transform, and fit_transform methods accept:

  • dask dataframes:

>>> import dask.dataframe as dd
>>> import pandas as pd
>>> X = dd.from_pandas(pd.DataFrame({'A': ['a', 'b', 'c'], 'B': ['d', 'd', 'd']}), npartitions=1)
  • koalas dataframes:

>>> import databricks.koalas as ks
>>> X = ks.DataFrame({'A': ['a', 'b', 'c'], 'B': ['d', 'd', 'd']})
  • and pandas dataframes:

>>> import pandas as pd
>>> X = pd.DataFrame({'A': ['a', 'b', 'c'], 'B': ['d', 'd', 'd']})

The result is a transformed dataframe belonging to the same dataframe library.

>>> obj.fit_transform(X)
   A
0  a
1  b
2  c
>>> X = pd.DataFrame({'A': ['a', 'b', 'c'], 'B': ['d', 'd', 'd']})
>>> _ = obj.fit(X)
>>> obj.transform_numpy(X.to_numpy())
array([['a'],
       ['b'],
       ['c']], dtype=object)
fit(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], y: Union[pd.Series, ks.Series, dd.Series] = None) → gators.data_cleaning.drop_low_cardinality.DropLowCardinality[source]

Fit the transformer on the dataframe X.

Get the list of column names to remove and the array of

indices to be kept.

Parameters
XDataFrame

Input dataframe.

ySeries, default None.

Target values.

Returns
——-
selfDropLowCardinality

Instance of itself.

static get_columns_to_drop(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], min_categories: float) → List[str][source]

Get the list of the column names to remove.

Parameters
Xpd.DataFrame

DataFrame.

min_categoriesint

Min categories allowed.

Returns
List[str]

List of the column names to drop.

static check_array(X: numpy.ndarray)

Validate array.

Parameters
Xnp.ndarray

Array.

check_array_is_numerics(X: numpy.ndarray)

Check if array is only numerics.

Parameters
Xnp.ndarray

Array.

static check_binary_target(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], y: Union[pd.Series, ks.Series, dd.Series])

Raise an error if the target is not binary.

Parameters
ySeries

Target values.

static check_dataframe(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame])

Validate dataframe.

Parameters
XDataFrame

Dataframe.

static check_dataframe_contains_numerics(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame])

Check if dataframe is only numerics.

Parameters
XDataFrame

Dataframe.

static check_dataframe_is_numerics(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame])

Check if dataframe is only numerics.

Parameters
XDataFrame

Dataframe.

check_dataframe_with_objects(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame])

Check if dataframe contains object columns.

Parameters
XDataFrame

Dataframe.

check_datatype(dtype, accepted_dtypes)

Check if dataframe is only numerics.

Parameters
XDataFrame

Dataframe.

static check_multiclass_target(y: Union[pd.Series, ks.Series, dd.Series])

Raise an error if the target is not discrete.

Parameters
ySeries

Target values.

check_nans(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], columns: List[str])

Raise an error if X contains NaN values.

Parameters
XDataFrame

Dataframe.

theta_vecList[float]

List of columns.

static check_regression_target(y: Union[pd.Series, ks.Series, dd.Series])

Raise an error if the target is not discrete.

Parameters
ySeries

Target values.

static check_target(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], y: Union[pd.Series, ks.Series, dd.Series])

Validate target.

Parameters
XDataFrame

Dataframe.

ySeries

Target values.

fit_transform(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame], y: Union[pd.Series, ks.Series, dd.Series] = None) → Union[pd.DataFrame, ks.DataFrame, dd.DataFrame]

Fit and Transform the dataframe X.

Parameters
XDataFrame.

Input dataframe.

ySeries, default None.

Input target.

Returns
XDataFrame

Transformed dataframe.

static get_column_names(inplace: bool, columns: List[str], suffix: str)

Return the names of the modified columns.

Parameters
inplacebool

If True return columns. If False return columns__suffix.

columnsList[str]

List of columns.

suffixstr

Suffix used if inplace is False.

Returns
List[str]

List of column names.

static get_idx_columns_to_keep(columns: List[str], columns_to_drop: List[str]) → numpy.array

Get the column indices to keep.

Parameters
theta_vecList[float]

List of columns of a dataset.

columns_to_dropList[str]

List of columns to drop.

Returns
np.array:

Column indices to keep.

get_params(deep=True)

Get parameters for this estimator.

Parameters
deepbool, default=True

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

Returns
paramsdict

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 Pipeline). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Parameters
**paramsdict

Estimator parameters.

Returns
selfestimator instance

Estimator instance.

transform(X: Union[pd.DataFrame, ks.DataFrame, dd.DataFrame]) → Union[pd.DataFrame, ks.DataFrame, dd.DataFrame]

Transform the dataframe X.

Parameters
XDataFrame

Input dataset.

Returns
XDataFrame

Transformed dataset.

transform_numpy(X: numpy.ndarray) → numpy.ndarray

Transform the array X.

Parameters
Xnp.ndarray

Input array.

Returns
Xnp.ndarray

Transformed array.