Comparing Ruby includes?() versus member?() performance

benchmark.rb

# frozen_string_literal: true

require "benchmark"

array = [4, 5, 6, 11, 12, 20, 40, 64, 65, 66, 81, 83].freeze
set = Set.new(array).freeze

n = 10_000_000

Benchmark.bm(10) do |x|
  x.report("INCLUDE array found at position 0") { n.times { array.include?(4) } }
  x.report("MEMBER  array found at position 0") { n.times { array.member?(4) } }
  x.report("INCLUDE array found at position 3") { n.times { array.include?(4) } }
  x.report("MEMBER  array found at position 3") { n.times { array.member?(4) } }
  x.report("INCLUDE array found at position 6") { n.times { array.include?(20) } }
  x.report("MEMBER  array found at position 6") { n.times { array.member?(20) } }
  x.report("INCLUDE array found at position 12") { n.times { array.include?(83) } }
  x.report("MEMBER  array found at position 12") { n.times { array.member?(83) } }
end

Benchmark.bm(10) do |x|
  x.report("INCLUDE set found at position 0") { n.times { set.include?(4) } }
  x.report("MEMBER  set found at position 0") { n.times { set.member?(4) } }
  x.report("INCLUDE set found at position 3") { n.times { set.include?(4) } }
  x.report("MEMBER  set found at position 3") { n.times { set.member?(4) } }
  x.report("INCLUDE set found at position 6") { n.times { set.include?(20) } }
  x.report("MEMBER  set found at position 6") { n.times { set.member?(20) } }
  x.report("INCLUDE set found at position 12") { n.times { set.include?(83) } }
  x.report("MEMBER  set found at position 12") { n.times { set.member?(83) } }
end

result.txt

# ARRAY

INCLUDE array found at position 0  0.435590   0.000751   0.436341 (  0.436900)
MEMBER  array found at position 0  1.842729   0.008922   1.851651 (  1.852418)
INCLUDE array found at position 3  0.428760   0.000787   0.429547 (  0.429682)
MEMBER  array found at position 3  1.812434   0.002646   1.815080 (  1.815789)
INCLUDE array found at position 6  0.647740   0.000819   0.648559 (  0.648889)
MEMBER  array found at position 6  2.501011   0.003785   2.504796 (  2.506374)
INCLUDE array found at position 12  0.939216   0.001906   0.941122 (  0.942874)
MEMBER  array found at position 12  3.236601   0.004980   3.241581 (  3.244097)

# SET

INCLUDE set found at position 0  0.498498   0.000447   0.498945 (  0.499263)
MEMBER  set found at position 0  0.500765   0.001357   0.502122 (  0.503197)
INCLUDE set found at position 3  0.498391   0.001104   0.499495 (  0.499727)
MEMBER  set found at position 3  0.499100   0.000217   0.499317 (  0.499470)
INCLUDE set found at position 6  0.498122   0.000302   0.498424 (  0.498533)
MEMBER  set found at position 6  0.500209   0.000485   0.500694 (  0.501011)
INCLUDE set found at position 12  0.497949   0.000381   0.498330 (  0.498489)
MEMBER  set found at position 12  0.504947   0.000892   0.505839 (  0.506567)

TLDR.md

member? is a method of Enumerable, which is WAY slower for Array but not for Set