compare Array#inject({}) to Array#map and Hash[]

inject_benchmark.rb

ATTRIBUTES = %w{aa bb cc dd ee ff gg}
ITERATION_COUNT = 100_000
DELTA_CHAR = "\u0394"

def self.hash_inject_time_elapsed
  start_time = Time.now
  ITERATION_COUNT.times do
    ATTRIBUTES.inject({}) {|h,s| h[s] = s.length; h }
  end
  Time.now - start_time
end

def self.map_and_hash_time_elapsed
  start_time = Time.now
  ITERATION_COUNT.times do
    Hash[ ATTRIBUTES.map {|s| [s, s.length] } ]
  end
  Time.now - start_time
end

def self.report_savings
  inject_time = hash_inject_time_elapsed
  map_time = map_and_hash_time_elapsed
  time_difference = inject_time - map_time
  savings_ratio = time_difference.to_f / inject_time
  "#{DELTA_CHAR} #{"%.2f" % (savings_ratio * 100)}%"
end