t.rb

ranking_org = (0..46).to_a

require 'benchmark'

Benchmark.bm 12 do |r|
  r.report "top3: range" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking[0..2]
    end
  end

  r.report "top3: length" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking[0, 3]
    end
  end

  r.report "top3: take" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking.take(3)
    end
  end

  r.report "lower: range" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking[3..46]
    end
  end

  r.report "lower: length" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking[3, 44]
    end
  end

  r.report "lower: drop" do
    10000000.times do
      ranking = ranking_org.dup
      top3 = ranking.drop(3)
    end
  end
end