# stratifiedSplitBySequence(proportions:by:on:generator:) Randomly split a MLDataTable into partitions on a user-define label column, while keeping rows from the same sequence in the original order. ``` func stratifiedSplitBySequence(proportions: [Double], by sequenceIdentifierColumn: String, on column: String, generator: inout RNG) throws -> MLDataTable where RNG : RandomNumberGenerator ``` ## Parameters `proportions` An array of values on [0,1] specifying the proprtions in each partition. Automatically normalized to 1. `sequenceIdentifierColumn` The sequence identifier column in an MLDataTable to identify rows of a sequence. `column` The column in an MLDataTable being stratified on. `generator` User-defined RandomNumberGenerator to use in stratification. ## Return Value A new MLDataTable with an additional partition column with the index of the partition for each row. ## Discussion The proportions specified will be applied uniformly to each label being partitioned on. --- 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)