Grouping an array by comparing 2 adjacent elements

Question

I have an array of objects and I would like to group them based on the difference between the attributes of 2 adjacent elements. The array is already sorted by that attribute. F

Answer 1

The following uses numerals directly, but the algorithm should be the same as when you do it with attributes. It assumes that all numerals are greater than 0. If not, then replace it with something that works.

array = [1, 3, 6, 9, 10]

[0, *array].each_cons(2).slice_before{|k, l| l - k > 2}.map{|a| a.map(&:last)}
# => [[1, 3], [6], [9, 10]]

With attributes, do l.attribute, etc., and replace 0 with a dummy element whose attribute is 0.