weather part of "data munging" kata

weather_kata.rb

require 'pp'

def lines(fn)
  File.open(fn) do |f|
    return f.readlines
  end
end

def data
  lines('weather.dat').map do |line|
    if line =~ /(\d+)\s+(\d+)\s+(\d+)/
      [$1, $2, $3].map { |col| col.to_i }
    end
  end.compact
end

strangest_day = data.max_by do |day, max, min|
  max - min
end

pp strangest_day