gistfile1.txt

$ ruby weather_split_vs_scan_benchmarks.rb 
      user     system      total        real
Using split  0.320000   0.010000   0.330000 (  0.330723)
Using scan  0.230000   0.020000   0.250000 (  0.239557)

weather_kata_split_vs_scan_benchmarks.rb

#!/usr/bin/env ruby

require 'benchmark'

Benchmark.bm do |x|
  x.report "Using split" do
    1000.times do
      File.read("weather.dat").each_line do |line|
        args = line.split(/\s+/)
        next unless args.length == 16
      end
    end
  end

  x.report "Using scan" do
    1000.times do
      File.read("weather.dat").each_line do |line|
        day, min_temp = line.scan(/\s+([0-9]+)\s+[0-9]+\s+([0-9]{2}).*/).first
        next if day.nil?
      end
    end
  end
end