benchmark_bound_method.rb

# frozen_string_literal: true

require "bundler/inline"

# Inline Gemfile for dependencies
gemfile(true) do
  source "https://rubygems.org"
  gem "benchmark-ips"
end

class MyClass
  NUMBERS = [1, 2, 3, 4, 5].freeze

  def as_block
    NUMBERS.map do |number|
      some_method(number)
    end
  end

  def as_bound_method
    NUMBERS.map(&method(:some_method))
  end

  def some_method(number)
    "Hello, World! #{number}"
  end
end

require "benchmark/ips"

instance = MyClass.new

Benchmark.ips do |x|
  x.report("as_block") { instance.as_block }
  x.report("as_bound_method") { instance.as_bound_method }
  x.compare!
end

❯ ruby benchmark_bound_method.rb
Fetching gem metadata from https://rubygems.org/.
Resolving dependencies...
Fetching benchmark-ips 2.14.0
Installing benchmark-ips 2.14.0
ruby 3.4.3 (2025-04-14 revision d0b7e5b6a0) +PRISM [arm64-darwin24]
Warming up --------------------------------------
            as_block   181.909k i/100ms
     as_bound_method   116.695k i/100ms
Calculating -------------------------------------
            as_block      1.879M (± 1.4%) i/s  (532.09 ns/i) -      9.459M in   5.034090s
     as_bound_method      1.137M (± 3.6%) i/s  (879.50 ns/i) -      5.718M in   5.035501s

Comparison:
            as_block:  1879392.9 i/s
     as_bound_method:  1137010.6 i/s - 1.65x  slower