A Benchmark of Array detect against lazy select and first

benchmark.rb

# A Benchmark of Array detect against lazy select and first
#
# Inspired by https://gist.github.com/ernie/1086770

require 'benchmark'

haystack = (1..1_000_000).to_a
needles = 1.upto(100).map {|n| n * 10_000}

puts "\n" + '=' * 80
puts "With in-block needle calculation"
puts '=' * 80

Benchmark.bmbm(10) do |x|
  x.report(:detect) do
    100.times { |n| haystack.detect { |v| v == 10_000 * n } }
  end

  x.report(:lazy) do
    100.times { |n| haystack.lazy.select { |v| v == 10_000 * n }.first }
  end

  x.report("select then first") do
    100.times { |n| haystack.select { |v| v == 10_000 * n }.first }
  end
end

puts "\n" + '=' * 80
puts "With precalculated needles"
puts '=' * 80

Benchmark.bmbm(10) do |x|
  x.report(:detect) do
    needles.each { |n| haystack.detect { |v| v == n } }
  end

  x.report(:lazy) do
    needles.each { |n| haystack.lazy.select { |v| v == n }.first }
  end

  x.report("select then first") do
    needles.each { |n| haystack.select { |v| v == n }.first }
  end
end

results

================================================================================
With in-block needle calculation
================================================================================
Rehearsal -----------------------------------------------------
detect              5.650000   0.010000   5.660000 (  5.694137)
lazy                6.660000   0.000000   6.660000 (  6.696257)
select then first   8.650000   0.030000   8.680000 (  8.705558)
------------------------------------------- total: 21.000000sec

                        user     system      total        real
detect              5.810000   0.010000   5.820000 (  5.862631)
lazy                7.280000   0.010000   7.290000 (  7.361647)
select then first   9.240000   0.040000   9.280000 (  9.326313)

================================================================================
With precalculated needles
================================================================================
Rehearsal -----------------------------------------------------
detect              4.410000   0.000000   4.410000 (  4.423517)
lazy                6.260000   0.010000   6.270000 (  6.305923)
select then first   6.570000   0.020000   6.590000 (  6.601375)
------------------------------------------- total: 17.270000sec

                        user     system      total        real
detect              4.430000   0.010000   4.440000 (  4.444339)
lazy                6.500000   0.010000   6.510000 (  6.577266)
select then first   6.880000   0.030000   6.910000 (  6.918666)