LabelEncoder
LabelEncoder is used to transform categorical array into array of numerical indices.
Import
import * as datacook from '@pipcook/datacook';
const { LabelEncoder } = datacook.Preprocess;
Constructor
const labelEncoder = new LabelEncoder({drop: 'first'});
Option in Prameters
| parameter | type | description |
|---|---|---|
drop optional | { ‘none’, ‘binary-only’, ‘first’ } | Specifies a method to drop one of the categories per feature. ‘none’: default, return all features ‘first’: drop the first categories in each feature ‘binary-only’: drop the first category in each feature with two categories. default=’none’ |
Properties
categories <Tensor1D>
One dimensional tensor of categories. Encoded result will be consistent with the order of categories appeared in this array.
drop <'first' | 'binary-only' | 'none'>
Drop method for this encoder.
Methods
init()
Initialize label encoder
Syntax
init(x: Tensor1D | number[] | string[]): Promise<void>
| parameter | type | description |
|---|---|---|
| x | Tensor1D | number[] | string[] | data input used to initialize encoder |
Example
const labelEncoder = new LabelEncoder();
await labelEncoder.init([ '1', '2', '3' ]);
encode()
Encode a given feature into numberic format
Syntax
async encode(x: Tensor | number[] | string[]): Promise<Tensor>
Parameters
| parameter | type | description |
|---|---|---|
| x | Tensor | number[] | string[] | original data need to encode |
Returns
<Tensor> transformed feature array
Example
const labelEncoder = new LabelEncoder();
await labelEncoder.init([ '1', '2', '3' ]);
const encoded = await labelEncoder.encode(['3', '3', '2']);
/**
* Tensor
* [2, 2, 1]
* /
decode()
Decode numeric array to original category array
Syntax
async decode(x: Tensor | RecursiveArray<number>): Promise<Tensor>
Parameters
| parameter | type | description |
|---|---|---|
| x | Tensor | number[] | numeric format data need to transform |
Returns
<Tensor> transformed category data
Example
const labelEncoder = new LabelEncoder();
await labelEncoder.init([ '1', '2', '3' ]);
const decoded = await labelEncoder.decode([ 1, 2, 2, 1, 0]);
decoded.print();
/**
* Tensor
* ['2', '3', '3', '2', '1']
* /