# StringEvaluator

> **Class** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/evaluation/schema/StringEvaluator)

String evaluator interface.

Grade, tag, or otherwise evaluate predictions relative to their inputs
and/or reference labels.

## Signature

```python
StringEvaluator()
```

## Extends

- `_EvalArgsMixin`
- `ABC`

## Properties

- `evaluation_name`
- `requires_reference`

## Methods

- [`evaluate_strings()`](https://reference.langchain.com/python/langchain-classic/evaluation/schema/StringEvaluator/evaluate_strings)
- [`aevaluate_strings()`](https://reference.langchain.com/python/langchain-classic/evaluation/schema/StringEvaluator/aevaluate_strings)

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/f0c5a28fa05adcda89aebcb449d897245ab21fa4/libs/langchain/langchain_classic/evaluation/schema.py#L136)