Class LengthBasedExampleSelector

A specialized example selector that selects examples based on their length, ensuring that the total length of the selected examples does not exceed a specified maximum length.

Example

const exampleSelector = new LengthBasedExampleSelector(
  [
    { input: "happy", output: "sad" },
    { input: "tall", output: "short" },
    { input: "energetic", output: "lethargic" },
    { input: "sunny", output: "gloomy" },
    { input: "windy", output: "calm" },
  ],
  {
    examplePrompt: new PromptTemplate({
      inputVariables: ["input", "output"],
      template: "Input: {input}\nOutput: {output}",
    }),
    maxLength: 25,
  },
);
const dynamicPrompt = new FewShotPromptTemplate({
  exampleSelector,
  examplePrompt: new PromptTemplate({
    inputVariables: ["input", "output"],
    template: "Input: {input}\nOutput: {output}",
  }),
  prefix: "Give the antonym of every input",
  suffix: "Input: {adjective}\nOutput:",
  inputVariables: ["adjective"],
});
console.log(dynamicPrompt.format({ adjective: "big" }));
console.log(
  dynamicPrompt.format({
    adjective:
      "big and huge and massive and large and gigantic and tall and much much much much much bigger than everything else",
  }),
);

Hierarchy

BaseExampleSelector
- LengthBasedExampleSelector

Index

Constructors

constructor

new LengthBasedExampleSelector(data): LengthBasedExampleSelector
Parameters
- data: LengthBasedExampleSelectorInput
Returns LengthBasedExampleSelector
Overrides BaseExampleSelector.constructor
- Defined in langchain-core/src/example_selectors/length_based.ts:74

Properties

examplePrompt

examplePrompt: PromptTemplate<any, any>

exampleTextLengths

exampleTextLengths: number[] = []

getTextLength

getTextLength: ((text) => number) = getLengthBased

Type declaration

- (text): number
- Parameters
  - text: string
  Returns number

maxLength

maxLength: number = 2048

`Protected` examples

examples: Example[] = []

Methods

addExample

addExample(example): Promise<void>
Adds an example to the list of examples and calculates its length.
Parameters
- example: Example
  
  The example to be added.
Returns Promise<void>
Promise that resolves when the example has been added and its length calculated.
Overrides BaseExampleSelector.addExample
- Defined in langchain-core/src/example_selectors/length_based.ts:86

calculateExampleTextLengths

calculateExampleTextLengths(v, values): Promise<number[]>
Calculates the lengths of the examples.
Parameters
- v: number[]
  
  Array of lengths of the examples.
- values: LengthBasedExampleSelector
  
  Instance of LengthBasedExampleSelector.
Returns Promise<number[]>
Promise that resolves with an array of lengths of the examples.
- Defined in langchain-core/src/example_selectors/length_based.ts:98

selectExamples

selectExamples(inputVariables): Promise<Example[]>
Selects examples until the total length of the selected examples reaches the maxLength.
Parameters
- inputVariables: Example
  
  The input variables for the examples.
Returns Promise<Example[]>
Promise that resolves with an array of selected examples.
Overrides BaseExampleSelector.selectExamples
- Defined in langchain-core/src/example_selectors/length_based.ts:119

toJSON

toJSON(): Serialized
Returns Serialized
Inherited from BaseExampleSelector.toJSON
- Defined in langchain-core/src/load/serializable.ts:140

toJSONNotImplemented

toJSONNotImplemented(): SerializedNotImplemented
Returns SerializedNotImplemented
Inherited from BaseExampleSelector.toJSONNotImplemented
- Defined in langchain-core/src/load/serializable.ts:214

`Static` fromExamples

fromExamples(examples, args): Promise<LengthBasedExampleSelector>
Creates a new instance of LengthBasedExampleSelector and adds a list of examples to it.
Parameters
- examples: Example[]
  
  Array of examples to be added.
- args: LengthBasedExampleSelectorInput
  
  Input parameters for the LengthBasedExampleSelector.
Returns Promise<LengthBasedExampleSelector>
Promise that resolves with a new instance of LengthBasedExampleSelector with the examples added.
- Defined in langchain-core/src/example_selectors/length_based.ts:146

Class LengthBasedExampleSelector

Example

Hierarchy

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

data: LengthBasedExampleSelectorInput

Returns LengthBasedExampleSelector

Properties

examplePrompt

exampleTextLengths

getTextLength

Type declaration

Parameters

text: string

Returns number

maxLength

Protected examples

Methods

addExample

Parameters

example: Example

Returns Promise<void>

calculateExampleTextLengths

Parameters

v: number[]

values: LengthBasedExampleSelector

Returns Promise<number[]>

selectExamples

Parameters

inputVariables: Example

Returns Promise<Example[]>

toJSON

Returns Serialized

toJSONNotImplemented

Returns SerializedNotImplemented

Static fromExamples

Parameters

examples: Example[]

args: LengthBasedExampleSelectorInput

Returns Promise<LengthBasedExampleSelector>

Settings

Member Visibility

Theme

On This Page

`Protected` examples

`Static` fromExamples