Starts with benchmark

benchmark.rb

require 'benchmark/ips'

Benchmark.ips do |x|
  records = []

  10_000.times do |i|
    records << "#{['abc', 'rec', 'air'].sample}-#{i}-#{['abc', 'rec', 'air'].sample}-#{i}"
  end

  AIRTABLE_ID_REGEX = /rec(?!_)/.freeze
  BETTER_AIRTABLE_ID_REGEX = /^rec(?!_)/.freeze

  x.report("regex") do |_times|
    selected = records.select do |record|
      record =~ AIRTABLE_ID_REGEX
    end
  end

  x.report("better regex") do |_times|
    selected = records.select do |record|
      record =~ BETTER_AIRTABLE_ID_REGEX
    end
  end

  x.report("start with") do |_times|
    selected = records.select do |record|
      record.start_with?('rec')
    end
  end

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

results.txt

Warming up --------------------------------------
               regex    30.469B i/100ms
        better regex    31.843B i/100ms
          start with   127.372B i/100ms
Calculating -------------------------------------
               regex      8.547T (± 5.3%) i/s -     42.627T in   5.002786s
        better regex      8.853T (± 6.1%) i/s -     44.039T in   5.000347s
          start with    147.412T (± 6.1%) i/s -    734.042T in   4.998314s

Comparison:
          start with: 147412033742104.2 i/s
        better regex: 8852860871996.6 i/s - 16.65x  (± 0.00) slower
               regex: 8546672631009.6 i/s - 17.25x  (± 0.00) slower