🦖

Codosaurus 🦖

#! /usr/bin/ruby

# Dave Thomas Code Kata 4, Data Munging.
# See http://codekata.pragprog.com/2007/01/kata_four_data_.html
# for purpose, and data files.
# Solution by Dave Aronson.

# Note: Could do these with File.readlines(file).each, but then
# I'd have to keep track of whether we'd read the header yet.


# Part 1: Weather Data

def min_weather_spread
  file = File.open 'weather.dat', 'r'
  first = file.gets.split[0] until first == 'Dy'
  min_spread = 9999  # unrealistically high value for this application
  while not file.eof?
    parts = file.gets.split
    next if parts.length == 0
    day = parts[0].to_i
    # to_i returns 0 on non-numeric; no exceptions thrown;
    # maybe there should be a String#is_numeric? method....
    break if day == 0
    spread = (parts[1].to_i - parts[2].to_i).abs
    if spread < min_spread
      min_spread = spread
      min_day = day
    end
  end
  puts "Min spread is #{min_spread}, on day #{min_day}"
  min_spread
end


# Part 2: Soccer League Table
# Soccer, football, whatever.  Most of the people reading this will be
# my fellow 'Murrikens, so I'll call it what we call it.

def min_soccer_spread
  file = File.open 'football.dat', 'r'
  first = file.gets.split[0] until first == 'Team'
  min_spread = 9999  # unrealistically high value for this application
  while not file.eof?
    parts = file.gets.split
    # data format is more consistent than weather one, so we can do this;
    # just be aware that in other applications, # of line parts may stay same.
    next if parts.length != 10
    spread = (parts[6].to_i - parts[8].to_i).abs
    if spread < min_spread
      min_spread = spread
      min_team = parts[1]
    end
  end
  puts "Min spread is #{min_spread}, for #{min_team}"
  min_spread
end


# Part 3: DRY Fusion.  Dry up the weather, and dry out the drunken football
# hooligans, er, I mean, soccer fans.  ;-)
#
# Note that the 9999 init, and skipping any where the first column evaluates to
# zero, works fine in THESE specific two cases, but may be problematic in other
# applications.  So why didn't I go ahead and make it fully generalized, such
# as by using the maximum supported number, or a parameter?  Another agile
# acronym: YAGNI.  If you don't grok it, Google it.

def min_spread filename, first_header, name_col, data_col_1, data_col_2
  file = File.open filename, 'r'
  first = file.gets.split[0] until first == first_header
  min_spread = 9999
  while not file.eof?
    parts = file.gets.split
    next if parts[0].to_i == 0
    spread = (parts[data_col_1].to_i - parts[data_col_2].to_i).abs
    if spread < min_spread
      min_spread = spread
      min_item = parts[name_col]
    end
  end
  # Could also have passed in a descriptor here, like 'day' or 'team'....
  puts "Min spread is #{min_spread}, for #{min_item}"
  min_spread
end


# TESTS


require 'test/unit'

class TC_MyTest < Test::Unit::TestCase

  def test_weather_case
    assert_equal min_spread('weather.dat', 'Dy', 0, 1, 2), min_weather_spread,
                 'Error: DRY equivalent does not work same as weather case'
  end

  def test_soccer_case
    assert_equal min_spread('football.dat', 'Team', 1, 6, 8), min_soccer_spread,
                 'Error: DRY equivalent does not work same as soccer case'

  end

end