Question

Ideally, I’d like a solution in Ruby or Javascript. Arrays instead of ranges in javascript would be fine.

I’d like input such as:

    [0..301, 230..268, 242..364, 574..579, 587..593]

or

    [0,301, 230,268, 242,364, 574,579, 587,593]

And turn it into something like:

    [0..230, 230..242, 242..268, 268..301, 301..364, 574..579, 587..593]

or

    [[0,230], [230,242, [242,268], [268,301], [301,364], [574,579, [587,593]]

Any help would be great. This sort of helps but not fully because it gives the full range instead of the chunked ranges, How do I summarize array of integers as an array of ranges?.

Answer 1

Here’s a ruby solution:

ranges = [0..301, 230..268, 242..364, 574..579, 587..593]
endpoints = ranges.map{|r| [r.first, r.last]}.flatten.sort
values = ranges.map{|r| r.to_a}.reduce(:+)

new_ranges = []
endpoints.reduce do |x, y|
    r = Range.new(x,y);
    new_ranges << r if r.all?{|v| values.include? v}
    y
end

puts new_ranges

#0..230
#230..242
#242..268
#268..301
#301..364
#574..579
#587..593