---
title: "add(_:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/nsmutableindexset/add(_:)-6dtkj"
---

# add(_:)

Adds an index  to the receiver.

## Declaration

```swift
func add(_ value: Int)
```

## Parameters

- `value`: Index to add. Must be in the range 0 .. NSNotFound - 1.

## See Also

### Related Documentation

- [Collections Programming Topics](apple-archive/documentation/Cocoa/Conceptual/Collections.md)

### Adding Indexes

- [add(_:)](foundation/nsmutableindexset/add(_:)-6zmti.md)
- [add(in:)](foundation/nsmutableindexset/add(in:).md)