# StringEvaluator

> **Class** in `langchain_google_vertexai`

📖 [View in docs](https://reference.langchain.com/python/langchain-google-vertexai/evaluators/_core/StringEvaluator)

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-google-vertexai/evaluators/_core/StringEvaluator/evaluate_strings)
- [`aevaluate_strings()`](https://reference.langchain.com/python/langchain-google-vertexai/evaluators/_core/StringEvaluator/aevaluate_strings)

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[View source on GitHub](https://github.com/langchain-ai/langchain-google/blob/a3f016b2a6c4af535df275545f76fa7424aa39e5/libs/vertexai/langchain_google_vertexai/evaluators/_core.py#L70)