concat vs flat_map

gistfile1.txt

require 'benchmark'
require 'action_view'
# include ActionView::Context
# include ActionView::Helpers::TextHelper

a = 'a'
b = 'b'
arr = %w(a b c d e f g h i)

Benchmark.bmbm(7) do |bm|
  bm.report('concat') do
    1000.times do
      cards = []
      arr.each_slice(6) do |a|
        cards.concat(a)
      end
    end
  end

  bm.report('flat_map') do
    1000.times do
      cards = []
      cards = arr.each_slice(6).flat_map do |a|
        a
      end
    end
  end
end