benchmark_array_to_hash.rb

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'benchmark-ips'
end

Benchmark.ips do |x|
  a = 10_000_000.times.map { |i| [i, i+2] }

  x.report('Hash[Array]') do
    Hash[a]
  end

  x.report('Array#to_h') do
    a.to_h
  end

  x.compare!
end

# Warming up --------------------------------------
#          Hash[Array]     1.000  i/100ms
#           Array#to_h     1.000  i/100ms
# Calculating -------------------------------------
#          Hash[Array]      0.181  (± 0.0%) i/s -      1.000  in   5.520885s
#           Array#to_h      0.169  (± 0.0%) i/s -      1.000  in   5.934197s
#
# Comparison:
#          Hash[Array]:        0.2 i/s
#           Array#to_h:        0.2 i/s - 1.07x slower