---
title: "length(_:)"
framework: simd
role: symbol
role_heading: Function
path: "simd/length(_:)-79i68"
---

# length(_:)

Returns the length of a vector.

## Declaration

```swift
func length(_ x: SIMD4<Double>) -> Double
```

## See Also

### Length and Distance Functions

- [length_squared(_:)](simd/length_squared(_:)-856uz.md)
- [distance(_:_:)](simd/distance(_:_:)-559m9.md)
- [distance_squared(_:_:)](simd/distance_squared(_:_:)-73nv3.md)