Idiomatic way to reject Ruby array elements by their index

Question

Given a Ruby array ary1, I'd like to produce another array ary2 that has the same elements as ary1, except for those at a given set of ary1 indices.

I can monkey-patch this functionality onto Ruby's Array class with

class Array
  def reject_at(*indices)
    copy = Array.new(self)
    indices.uniq.sort.reverse_each do |i|
      copy.delete_at i
    end
    return copy
  end
end

which I can then use like this:

ary1 = [:a, :b, :c, :d, :e]
ary2 = ary1.reject_at(2, 4)
puts(ary2.to_s) # [:a, :b, :d]

While this works fine, I have the feeling that I must be missing something obvious. Is there some functionality like this already built into Ruby? E.g., can and should Array#slice be used for this task?

Answer 1

Don't think there is an inbuilt solution for this. Came up with the following:

ary1 = [:a, :b, :c, :d, :e]
indexes_to_reject = [1,2,3]

ary1.reject.each_with_index{|i, ix| indexes_to_reject.include? ix }