# StringRunMapper

> **Class** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/smith/evaluation/string_run_evaluator/StringRunMapper)

Extract items to evaluate from the run object.

## Signature

```python
StringRunMapper()
```

## Extends

- `Serializable`

## Properties

- `output_keys`

## Methods

- [`map()`](https://reference.langchain.com/python/langchain-classic/smith/evaluation/string_run_evaluator/StringRunMapper/map)

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/9f232caa7a8fe1ca042a401942d5d90d54ceb1a6/libs/langchain/langchain_classic/smith/evaluation/string_run_evaluator.py#L38)