---
title: "custom(of:label:_:)"
framework: evaluations
role: symbol
role_heading: Instance Method
path: "evaluations/metricsaggregator/custom(of:label:_:)"
---

# custom(of:label:_:)

Computes a custom aggregation from a single metric’s results.

## Declaration

```swift
mutating func custom(of metric: Metric, label: String, _ body: ([Double]) -> Double)
```

## Parameters

- `metric`: The metric to aggregate.
- `label`: The label for this statistic in the aggregated results.
- `body`: A closure that receives the metric’s values and returns a computed statistic.