sort vs sort_by for intensive operation

sort_vs_sort_by.rb

require 'benchmark'

root_directories = Dir.glob("/*")

n = 5000
Benchmark.bm do |x|
  x.report("sort") do
    n.times{ root_directories.sort { |a, b| File.ctime(a) <=> File.ctime(b) } }
  end

  x.report("sort_by") do
    n.times{ root_directories.sort_by { |dir| File.ctime(dir) } }
  end
end