---
title: "index(after:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/lazyprefixwhilesequence/index(after:)"
---

# index(after:)

Returns the position immediately after the given index.

## Declaration

```swift
func index(after i: LazyPrefixWhileSequence<Base>.Index) -> LazyPrefixWhileSequence<Base>.Index
```

## Parameters

- `i`: A valid index of the collection. i must be less than endIndex.

## Return Value

Return Value The index value immediately after i.

## Discussion

Discussion The successor of an index must be well defined. For an index i into a collection c, calling c.index(after: i) returns the same index every time.