change_array.rb

require 'benchmark'

def steps_each(arr_a, arr_b)
  h_a = arr_a.to_h
  h_b = arr_b.to_h

  result = []
  h_a.keys.each do |k|
    if h_b.member?(k)
      result << [k, 'update', h_b[k]] if h_b[k] != h_a[k]
    else
      result << [k, 'delete']
    end
  end

  h_b.keys.each do |k|
    result << [k, 'create', h_b[k]] unless h_a.member?(k)
  end
  result
end

def steps_diff(arr_a, arr_b)
  h_a = arr_a.to_h
  h_b = arr_b.to_h

  result = []
  (h_a.keys - h_b.keys).each { |k| result << [k, 'delete'] }
  (h_a.keys & h_b.keys).each { |k| result << [k, 'update', h_b[k]] if h_b[k] != h_a[k]}
  (h_b.keys - h_a.keys).each { |k| result << [k, 'create', h_b[k]] }

  result
end

a = []
rand(100).times {a << [('a'..'z').to_a.sample, rand(50)]}
b = []
rand(100).times {b << [('a'..'z').to_a.sample, rand(50)]}

puts steps_each(a,b).inspect

Benchmark.bm(10) do |x|
  x.report('each:') { steps_each(a, b) }
  x.report('diff:') { steps_diff(a, b) }
end