Planned⎕Partition Partition To Group r←⎕Partition y

This primitive or feature is planned, that is, it doesn't appear in the most recent released implementation of TinyAPL. Details may change before it is added!
Category: Core

y is an integer vector representing a partition of an array as defined by the APL function Partition. r is the result of converting it to a representation that is suitable for Group: r←+⍆2<⍅↡0⍪y.