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# RandomAccessCollection Implementations

## Topics

### Instance Properties

[`var endIndex: Int`](/documentation/TabularData/RowGrouping/endIndex)

The index of the final group in the row grouping.

[`var startIndex: Int`](/documentation/TabularData/RowGrouping/startIndex)

The index of the initial group in the row grouping.

### Instance Methods

[`func index(after: Int) -> Int`](/documentation/TabularData/RowGrouping/index(after:))

Returns the index immediately after an element index.

[`func index(before: Int) -> Int`](/documentation/TabularData/RowGrouping/index(before:))

Returns the index immediately before an element index.

### Subscripts

[`subscript(Int) -> (key: GroupingKey?, group: DataFrame.Slice)`](/documentation/TabularData/RowGrouping/subscript(_:)-5z2eg)

Retrieves a group at an index.

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