# BidirectionalCollection Implementations ## Topics ### Instance Properties [`var endIndex: Int`](/documentation/TabularData/Column/endIndex) The index of the final element in the column. [`var startIndex: Int`](/documentation/TabularData/Column/startIndex) The index of the initial element in the column. ### Instance Methods [`func index(after: Int) -> Int`](/documentation/TabularData/Column/index(after:)) Returns the index immediately after an element index. [`func index(before: Int) -> Int`](/documentation/TabularData/Column/index(before:)) Returns the index immediately before an element index. ### Subscripts [`subscript(Range) -> ColumnSlice`](/documentation/TabularData/Column/subscript(_:)-gne9) Accesses a contiguous range of elements. [`subscript(Int) -> Column.Element`](/documentation/TabularData/Column/subscript(_:)-qm4d) Accesses an element at an index. --- Copyright © 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)