---
title: String.Index
framework: swift
role: symbol
role_heading: Structure
path: swift/string/index
---

# String.Index

A position of a character or code unit in a string.

## Declaration

```swift
@frozen struct Index
```

## Topics

### Initializers

- [init(_:within:)](swift/string/index/init(_:within:)-2txd4.md)
- [init(_:within:)](swift/string/index/init(_:within:)-2u3iq.md)
- [init(_:within:)](swift/string/index/init(_:within:)-379kg.md)
- [init(_:within:)](swift/string/index/init(_:within:)-3eir6.md)
- [init(_:within:)](swift/string/index/init(_:within:)-5lb6l.md)
- [init(_:within:)](swift/string/index/init(_:within:)-7e1rw.md)
- [init(encodedOffset:)](swift/string/index/init(encodedoffset:).md)
- [init(utf16Offset:in:)](swift/string/index/init(utf16offset:in:).md)

### Instance Properties

- [encodedOffset](swift/string/index/encodedoffset.md)

### Instance Methods

- [samePosition(in:)](swift/string/index/sameposition(in:)-3mz95.md)
- [samePosition(in:)](swift/string/index/sameposition(in:)-4yeo1.md)
- [samePosition(in:)](swift/string/index/sameposition(in:)-6oxfv.md)
- [samePosition(in:)](swift/string/index/sameposition(in:)-86cct.md)
- [utf16Offset(in:)](swift/string/index/utf16offset(in:).md)

### Default Implementations

- [Comparable Implementations](swift/string/index/comparable-implementations.md)
- [CustomDebugStringConvertible Implementations](swift/string/index/customdebugstringconvertible-implementations.md)
- [Equatable Implementations](swift/string/index/equatable-implementations.md)
- [Hashable Implementations](swift/string/index/hashable-implementations.md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)
- [Comparable](swift/comparable.md)
- [Copyable](swift/copyable.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Escapable](swift/escapable.md)
- [Hashable](swift/hashable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Related String Types

- [Substring](swift/substring.md)
- [StringProtocol](swift/stringprotocol.md)
- [String.UnicodeScalarView](swift/string/unicodescalarview.md)
- [String.UTF16View](swift/string/utf16view.md)
- [String.UTF8View](swift/string/utf8view.md)
- [String.Iterator](swift/string/iterator.md)
- [String.Encoding](swift/string/encoding.md)