My own benchmarks on each_with_object

benchmark.rb

require 'benchmark'
array = [1, 2, 3]
iterations = 1_000_000

def method_one(array)
  hash = {}
  array.each do |integer|
    hash[integer] = integer ** 2
  end
  hash
end

def method_two(array)
  {}.tap do |hash|
    array.each do |integer|
      hash[integer] = integer ** 2
    end
  end
end


def method_three(array)
  array.each_with_object({}) do |integer, hash|
     hash[integer] = integer ** 2
  end
end

Benchmark.bm(7) do |x|
  x.report("method one") do
    iterations.times do
      method_one(array)
    end
  end
  
  x.report("method two") do
    iterations.times do
      method_two(array)
    end
  end

  x.report("method three") do
    iterations.times do
      method_three(array)
    end
  end
end

# chrisj@scruffy ~/projects $ ruby benchmark.rb
#                user       system     total        real
# method one    3.050000   0.010000   3.060000    (  3.530709)
# method two    3.390000   0.000000   3.390000    (  3.635153)
# method three  4.120000   0.000000   4.120000    (  4.400589)