MinMaxScaler (original) (raw)

class sklearn.preprocessing.MinMaxScaler(feature_range=(0, 1), *, copy=True, clip=False)[source]#

Transform features by scaling each feature to a given range.

This estimator scales and translates each feature individually such that it is in the given range on the training set, e.g. between zero and one.

The transformation is given by:

X_std = (X - X.min(axis=0)) / (X.max(axis=0) - X.min(axis=0)) X_scaled = X_std * (max - min) + min

where min, max = feature_range.

This transformation is often used as an alternative to zero mean, unit variance scaling.

MinMaxScaler doesn’t reduce the effect of outliers, but it linearly scales them down into a fixed range, where the largest occurring data point corresponds to the maximum value and the smallest one corresponds to the minimum value. For an example visualization, refer to Compare MinMaxScaler with other scalers.

Read more in the User Guide.

Parameters:

feature_rangetuple (min, max), default=(0, 1)

Desired range of transformed data.

copybool, default=True

Set to False to perform inplace row normalization and avoid a copy (if the input is already a numpy array).

clipbool, default=False

Set to True to clip transformed values of held-out data to provided feature range.

Added in version 0.24.

Attributes:

**min_**ndarray of shape (n_features,)

Per feature adjustment for minimum. Equivalent tomin - X.min(axis=0) * self.scale_

**scale_**ndarray of shape (n_features,)

Per feature relative scaling of the data. Equivalent to(max - min) / (X.max(axis=0) - X.min(axis=0))

Added in version 0.17: scale_ attribute.

**data_min_**ndarray of shape (n_features,)

Per feature minimum seen in the data

Added in version 0.17: data_min_

**data_max_**ndarray of shape (n_features,)

Per feature maximum seen in the data

Added in version 0.17: data_max_

**data_range_**ndarray of shape (n_features,)

Per feature range (data_max_ - data_min_) seen in the data

Added in version 0.17: data_range_

**n_features_in_**int

Number of features seen during fit.

Added in version 0.24.

**n_samples_seen_**int

The number of samples processed by the estimator. It will be reset on new calls to fit, but increments acrosspartial_fit calls.

**feature_names_in_**ndarray of shape (n_features_in_,)

Names of features seen during fit. Defined only when Xhas feature names that are all strings.

Added in version 1.0.

See also

minmax_scale

Equivalent function without the estimator API.

Notes

NaNs are treated as missing values: disregarded in fit, and maintained in transform.

Examples

from sklearn.preprocessing import MinMaxScaler data = [[-1, 2], [-0.5, 6], [0, 10], [1, 18]] scaler = MinMaxScaler() print(scaler.fit(data)) MinMaxScaler() print(scaler.data_max_) [ 1. 18.] print(scaler.transform(data)) [[0. 0. ] [0.25 0.25] [0.5 0.5 ] [1. 1. ]] print(scaler.transform([[2, 2]])) [[1.5 0. ]]

fit(X, y=None)[source]#

Compute the minimum and maximum to be used for later scaling.

Parameters:

Xarray-like of shape (n_samples, n_features)

The data used to compute the per-feature minimum and maximum used for later scaling along the features axis.

yNone

Ignored.

Returns:

selfobject

Fitted scaler.

fit_transform(X, y=None, **fit_params)[source]#

Fit to data, then transform it.

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

Parameters:

Xarray-like of shape (n_samples, n_features)

Input samples.

yarray-like of shape (n_samples,) or (n_samples, n_outputs), default=None

Target values (None for unsupervised transformations).

**fit_paramsdict

Additional fit parameters.

Returns:

X_newndarray array of shape (n_samples, n_features_new)

Transformed array.

get_feature_names_out(input_features=None)[source]#

Get output feature names for transformation.

Parameters:

input_featuresarray-like of str or None, default=None

Input features.

Returns:

feature_names_outndarray of str objects

Same as input features.

get_metadata_routing()[source]#

Get metadata routing of this object.

Please check User Guide on how the routing mechanism works.

Returns:

routingMetadataRequest

A MetadataRequest encapsulating routing information.

get_params(deep=True)[source]#

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.

inverse_transform(X)[source]#

Undo the scaling of X according to feature_range.

Parameters:

Xarray-like of shape (n_samples, n_features)

Input data that will be transformed. It cannot be sparse.

Returns:

Xtndarray of shape (n_samples, n_features)

Transformed data.

partial_fit(X, y=None)[source]#

Online computation of min and max on X for later scaling.

All of X is processed as a single batch. This is intended for cases when fit is not feasible due to very large number ofn_samples or because X is read from a continuous stream.

Parameters:

Xarray-like of shape (n_samples, n_features)

The data used to compute the mean and standard deviation used for later scaling along the features axis.

yNone

Ignored.

Returns:

selfobject

Fitted scaler.

set_output(*, transform=None)[source]#

Set output container.

See Introducing the set_output APIfor an example on how to use the API.

Parameters:

transform{“default”, “pandas”, “polars”}, default=None

Configure output of transform and fit_transform.

Added in version 1.4: "polars" option was added.

Returns:

selfestimator instance

Estimator instance.

set_params(**params)[source]#

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)[source]#

Scale features of X according to feature_range.

Parameters:

Xarray-like of shape (n_samples, n_features)

Input data that will be transformed.

Returns:

Xtndarray of shape (n_samples, n_features)

Transformed data.