Grouping adjacent elements in a list

Question

Let's say I want to write a function that does this:

input: [1,1,3,3,4,2,2,5,6,6] output: [[1,1],[3,3],[4],[2,2],[5],[6,6]]

It's grouping adjacent elements that are same.

What should the name of this method be? Is there a standard name for this operation?

Answer 1

In [1,1,3,3,4,2,2,5,6,6], a thing like [1,1] is very often referred to as run (as in run-length encoding, see RLE in Scala). I'd therefore call the method groupRuns.