Compare s.hex.chr vs [s.hex].pack('C') vs [s.hex].pack(C)

bench.rb

require 'benchmark/ips'
require 'securerandom'

Benchmark.ips do |x|
  C = 'C'.freeze
  DATA = (1..1_000_000).map { SecureRandom.hex(1) }

  x.report("hex.chr") do |times|
    i = 0
    while i < times
      DATA[i%1_000_000].hex.chr
      i += 1
    end
  end
  x.report("array pack C") do |times|
    i = 0
    while i < times
      [DATA[i%1_000_000].hex].pack(C)
      i += 1
    end
  end
  x.report("array pack 'C'") do |times|
    i = 0
    while i < times
      [DATA[i%1_000_000].hex].pack('C')
      i += 1
    end
  end

  # Compare the iterations per second of the various reports!
  x.compare!
end

results.txt

Warming up --------------------------------------
             hex.chr   112.897k i/100ms
        array pack C    79.043k i/100ms
      array pack 'C'    76.455k i/100ms
Calculating -------------------------------------
             hex.chr      5.030M (±10.8%) i/s -     24.837M
        array pack C      1.794M (±10.3%) i/s -      8.932M
      array pack 'C'      1.535M (± 9.1%) i/s -      7.646M

Comparison:
             hex.chr:  5030277.2 i/s
        array pack C:  1793749.5 i/s - 2.80x slower
      array pack 'C':  1535189.2 i/s - 3.28x slower