# subscript(_:) Creates a subset of the table by masking the rows with the given untyped column. ``` subscript(mask: MLUntypedColumn) -> MLDataTable { get } ``` ## Parameters `mask` An untyped column indicating whether rows should be removed (a default value) or included (any nondefault value) in the derived table. ## Return Value A new data table. ## Overview Use this untyped column–based subscript to create a new table by masking a subset of the table rows. The derived table will not include rows where `mask` contains a default value for its underlying type, such as: - `0` in untyped `Int` columns - `0.0` in untyped `Double` columns - An empty string in untyped `String` columns The derived data table includes rows where the masking column has any other (nondefault) value. -10r4l-1@2x.png) For example, to filter the values in a data table as shown above, begin by creating a table with the original data. ```swift let data: [String: MLDataValueConvertible] = [ "Title": ["Alice in Wonderland", "Hamlet", "Dracula", "Peter Pan", "The Great Gatsby"], "Genre": ["Fantasy", "Drama", "Adventure", "Fantasy", "Drama"], "Pages": [124, 98, 0, 94, 0] ] guard let table = try? MLDataTable(dictionary: data) else { fatalError("Invalid dictionary data") } ``` After you create the table, use the `String`-based [`subscript(_:)`](/documentation/CreateML/MLDataTable/subscript(_:)-3wjk) to extract a column. ```swift // Create a new untyped column "pagesColumn" copied from the table’s "Pages" column let pagesColumn = table["Pages"] ``` Use `subscript(mask: MLUntypedColumn)` with an untyped column–row mask to create a filtered table. The subscript uses the untyped values to determine whether to keep a row. In this example, the untyped column `pagesColumn` has an underlying type of `Int`. The subscript removes any row with a value of `0` (the default value for `Int`) and keeps all other rows. ```swift // Filter the table using pagesColumn. // Each row with a value of 0 is removed. let validPageCountTable = table[pagesColumn] ``` --- 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)