# comparison_evaluator

> **Function** in `langsmith`

📖 [View in docs](https://reference.langchain.com/python/langsmith/evaluation/evaluator/comparison_evaluator)

Create a comaprison evaluator from a function.

## Signature

```python
comparison_evaluator(
    func: Callable[[Sequence[Run], Optional[Example]], Union[_COMPARISON_OUTPUT, Awaitable[_COMPARISON_OUTPUT]]],
) -> DynamicComparisonRunEvaluator
```

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[View source on GitHub](https://github.com/langchain-ai/langsmith-sdk/blob/15468f97c18467d67ececb90b17107b0875e7a65/python/langsmith/evaluation/evaluator.py#L653)