From DojoWiki

The final solution is directly below, which was refactored from this solution

class Weather

  def getMinTempDiff(filename)
    minTempDifference = maxvalue
    File.open(filename).each { |line|

      maxValue =  getByIndex(line, 1)
      minValue =  getByIndex(line, 2)

      if (maxValue == nil || minValue == nil) 
        next
      end

      difference = (maxValue - minValue)
      if (difference < minTempDifference) 
        minTempDifference = difference
      end

    }

    return minTempDifference
  end

  def getByIndex( line, index )
    str = line.split(' ')[index]
    if (str !=  nil && str.index("*") != nil)
      str = str.slice(0, str.index("*"))
    end
    
    if (str != nil)
      begin
        value = Float(str)
      rescue
        value = nil
      end
    end
    value
  end

  def maxvalue
    return 99999
  end
end

require 'test/unit'
require 'weather.rb'

class TestWeather < Test::Unit::TestCase

  def test_output
    weather = Weather.new
    s=2
    assert_equal(2, weather.getValue('K4Weather.txt'))
  end

end

Original Solution

class Weather

def getValue(filename)
    tempValue = nil
    File.open(filename).each { |line|
    maxStr = line.split(' ')[1]
    minStr = line.split(' ')[2]
    if (maxStr !=  nil && maxStr.index("*") != nil)
      maxStr = maxStr.slice(0, maxStr.index("*"))
    end
    
    if (minStr != nil && minStr.index("*") != nil)
      minStr = minStr.slice(0, minStr.index("*"))
    end
    if (minStr != nil && maxStr != nil)
      begin
	minValue = Float(minStr)
      rescue
	puts "Failed " + $!
      end
      begin
	maxValue = Float(maxStr)
      rescue
	puts "Failed " + $!
      end
      if (maxValue != nil && minValue != nil)
	value = (maxValue - minValue)
	if (tempValue == nil) 
	  tempValue = minValue 
	end
	
	if (value < tempValue) 
	  tempValue = value
	end
      end
    end
    puts tempValue.to_s
    return 2
  }
end

end