Question

I’ve got an array of classes, and I want to find where there may be a schedule overlap.

My array is something like this

[
  {
    id:2,
    start: "3:30",
    length: 40,
    break: 30,
    num_attendees: 14
  },
  {
    id: 3,
    start: "3: 40",
    length: 60,
    break: 40,
    num_attendees: 4
  },
  {
    id: 4,
    start: "4: 40",
    length: 30,
    break: 10,
    num_attendees: 40
  }
]

pretty simple.
Now, I want to get an array where I add the start and the length, and then get the classes that overlap to notify the user that they have a conflict.

I know I can do a large for loop and compare that way, but I’m thinking there must be a nicer way to do this in Ruby, something like (ignore that we’re not working in absolute minutes here, I’ve got that, I just want to keep the example simple).

overlap = class_list.select{|a,b| if a.start+a.length>b.start return a,b end}

any suggestions?

Answer 1

You can use Array#combination like this:

class_list.combination(2).select{|c1, c2|
  # here check if c1 and c2 overlap
}