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# subscript(_:)

Provides the number at the subscripted index.

```
@nonobjc subscript(index: Int32) -> CUnsignedChar { get }
```

## Discussion

This subscript operates on one-component geometry sources with a [`format`](/documentation/ARKit/ARGeometrySource/format) of <doc://com.apple.documentation/documentation/Metal/MTLVertexFormat/uchar>, such as [`classification`](/documentation/ARKit/ARMeshGeometry/classification).

---

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