Ruby benchmark of symbol lookup in case statement vs Hash

case_vs_hash.rb

# results on Ruby 3.2:
#
# Warming up --------------------------------------
#                 hash     1.910M i/100ms
#                 case     1.297M i/100ms
# Calculating -------------------------------------
#                 hash     19.029M (± 1.5%) i/s -     95.507M in   5.020123s
#                 case     12.604M (± 0.4%) i/s -     63.534M in   5.040776s
#
# Comparison:
#                 hash: 19029244.0 i/s
#                 case: 12604156.7 i/s - 1.51x  (± 0.00) slower

require 'benchmark/ips'

arg = :m
hash = ('a'..'z').to_h { |c| [c.to_sym, c] }

Benchmark.ips do |x|
  x.report('hash') { hash[arg] }
  x.report('case') do
    case arg
    when :a ; 'a'
    when :b ; 'b'
    when :c ; 'c'
    when :d ; 'd'
    when :e ; 'e'
    when :f ; 'f'
    when :g ; 'g'
    when :h ; 'h'
    when :i ; 'i'
    when :j ; 'j'
    when :k ; 'k'
    when :l ; 'l'
    when :m ; 'm'
    when :n ; 'n'
    when :o ; 'o'
    when :p ; 'p'
    when :q ; 'q'
    when :r ; 'r'
    when :s ; 's'
    when :t ; 't'
    when :u ; 'u'
    when :v ; 'v'
    when :w ; 'w'
    when :x ; 'x'
    when :y ; 'y'
    when :z ; 'z'
    end
  end
  x.compare!
end