<!--
{
  "availability" : [
    "iOS: 8.0.0 -",
    "iPadOS: 8.0.0 -",
    "macCatalyst: 13.0.0 -",
    "macOS: 10.10.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 2.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Swift",
  "identifier" : "/documentation/Swift/UnsafeMutableRawBufferPointer/subscript(_:)-u791",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Subscript",
  "symbol" : {
    "kind" : "Instance Subscript",
    "modules" : [
      "Swift"
    ],
    "preciseIdentifier" : "s:Swys5UInt8VSicip"
  },
  "title" : "subscript(_:)"
}
-->

# subscript(_:)

Accesses the byte at the given offset in the memory region as a `UInt8`
value.

```
subscript(i: Int) -> UnsafeMutableRawBufferPointer.Element { get nonmutating set }
```

## Parameters

`i`

The offset of the byte to access. `i` must be in the range
`0..<count`.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)