val of_pyobject : Py.Object.t -> tval to_pyobject : t -> Py.Object.tval create :
?neg_label:int ->
?pos_label:int ->
?sparse_output:bool ->
unit ->
tBinarize labels in a one-vs-all fashion
Several regression and binary classification algorithms are available in scikit-learn. A simple way to extend these algorithms to the multi-class classification case is to use the so-called one-vs-all scheme.
At learning time, this simply consists in learning one regressor or binary classifier per class. In doing so, one needs to convert multi-class labels to binary labels (belong or does not belong to the class). LabelBinarizer makes this process easy with the transform method.
At prediction time, one assigns the class for which the corresponding model gave the greatest confidence. LabelBinarizer makes this easy with the inverse_transform method.
Read more in the :ref:`User Guide <preprocessing_targets>`.
Parameters ----------
neg_label : int (default: 0) Value with which negative labels must be encoded.
pos_label : int (default: 1) Value with which positive labels must be encoded.
sparse_output : boolean (default: False) True if the returned array from transform is desired to be in sparse CSR format.
Attributes ----------
classes_ : array of shape n_class Holds the label for each class.
y_type_ : str, Represents the type of the target data as evaluated by utils.multiclass.type_of_target. Possible type are 'continuous', 'continuous-multioutput', 'binary', 'multiclass', 'multiclass-multioutput', 'multilabel-indicator', and 'unknown'.
sparse_input_ : boolean, True if the input data to transform is given as a sparse matrix, False otherwise.
Examples -------- >>> from sklearn import preprocessing >>> lb = preprocessing.LabelBinarizer() >>> lb.fit(1, 2, 6, 4, 2) LabelBinarizer() >>> lb.classes_ array(1, 2, 4, 6) >>> lb.transform(1, 6) array([1, 0, 0, 0],
[0, 0, 0, 1])
Binary targets transform to a column vector
>>> lb = preprocessing.LabelBinarizer() >>> lb.fit_transform('yes', 'no', 'no', 'yes') array([1],
[0],
[0],
[1])
Passing a 2D matrix for multilabel classification
>>> import numpy as np >>> lb.fit(np.array([0, 1, 1], [1, 0, 0])) LabelBinarizer() >>> lb.classes_ array(0, 1, 2) >>> lb.transform(0, 1, 2, 1) array([1, 0, 0],
[0, 1, 0],
[0, 0, 1],
[0, 1, 0])
See also -------- label_binarize : function to perform the transform operation of LabelBinarizer with fixed classes. sklearn.preprocessing.OneHotEncoder : encode categorical features using a one-hot aka one-of-K scheme.
Fit label binarizer
Parameters ---------- y : array of shape n_samples, or n_samples, n_classes Target values. The 2-d matrix should only contain 0 and 1, represents multilabel classification.
Returns ------- self : returns an instance of self.
val fit_transform :
y:[ `Ndarray of Ndarray.t | `SparseMatrix of Csr_matrix.t ] ->
t ->
Ndarray.tFit label binarizer and transform multi-class labels to binary labels.
The output of transform is sometimes referred to as the 1-of-K coding scheme.
Parameters ---------- y : array or sparse matrix of shape n_samples, or n_samples, n_classes Target values. The 2-d matrix should only contain 0 and 1, represents multilabel classification. Sparse matrix can be CSR, CSC, COO, DOK, or LIL.
Returns ------- Y : array or CSR matrix of shape n_samples, n_classes Shape will be n_samples, 1 for binary problems.
val get_params : ?deep:bool -> t -> Py.Object.tGet 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.
val inverse_transform :
?threshold:[ `Float of float | `None ] ->
y:[ `Ndarray of Ndarray.t | `PyObject of Py.Object.t ] ->
t ->
Py.Object.tTransform binary labels back to multi-class labels
Parameters ---------- Y : numpy array or sparse matrix with shape n_samples, n_classes Target values. All sparse matrices are converted to CSR before inverse transformation.
threshold : float or None Threshold used in the binary and multi-label cases.
Use 0 when ``Y`` contains the output of decision_function (classifier). Use 0.5 when ``Y`` contains the output of predict_proba.
If None, the threshold is assumed to be half way between neg_label and pos_label.
Returns ------- y : numpy array or CSR matrix of shape n_samples Target values.
Notes ----- In the case when the binary labels are fractional (probabilistic), inverse_transform chooses the class with the greatest value. Typically, this allows to use the output of a linear model's decision_function method directly as the input of inverse_transform.
val set_params : ?params:(string * Py.Object.t) list -> t -> tSet 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.
val transform :
y:[ `Ndarray of Ndarray.t | `SparseMatrix of Csr_matrix.t ] ->
t ->
Ndarray.tTransform multi-class labels to binary labels
The output of transform is sometimes referred to by some authors as the 1-of-K coding scheme.
Parameters ---------- y : array or sparse matrix of shape n_samples, or n_samples, n_classes Target values. The 2-d matrix should only contain 0 and 1, represents multilabel classification. Sparse matrix can be CSR, CSC, COO, DOK, or LIL.
Returns ------- Y : numpy array or CSR matrix of shape n_samples, n_classes Shape will be n_samples, 1 for binary problems.
val y_type_ : t -> stringAttribute y_type_: see constructor for documentation
val sparse_input_ : t -> boolAttribute sparse_input_: see constructor for documentation
val to_string : t -> stringPrint the object to a human-readable representation.
val show : t -> stringPrint the object to a human-readable representation.
val pp : Format.formatter -> t -> unitPretty-print the object to a formatter.