Module: MetricConversions

Defined in:
lib/metric_conversions/areas.rb,
lib/metric_conversions/lengths.rb,
lib/metric_conversions/version.rb,
lib/metric_conversions/volumes.rb,
lib/metric_conversions/temperatures.rb

Defined Under Namespace

Classes: Area

Constant Summary collapse

VERSION = 
"0.0.2"

Instance Method Summary collapse

Instance Method Details

#convert(from, to) ⇒ Object

performs the actual unit length conversion given a value



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# File 'lib/metric_conversions/lengths.rb', line 14

def convert(from, to)
  # if we are converting from a metric value
  if(is_metric?(from))
      # because from is metric, convert to centimeters
      cm = self.to_cm(from)

      # if we are converting to a metric value, convert the value
      if(is_metric?(to))
        if(to == "mm")
          cm.to_mm.round_2

        elsif(to == "cm")
          cm.round_2

        elsif(to == "m")
          cm.to_m.round_2

        elsif(to == "km")
          cm.to_km.round_2
        end

      # the value we are converting to is not metric, so convert the value to inches
      else
        inches = cm.to_inches("cm")

        # if we are converting to English values, perform the conversion
        if(to == "in")
          inches.round_2

        elsif(to == "ft")
          inches.to_ft.round_2

        elsif(to == "yd")
          inches.to_yd.round_2

        elsif(to == "mi")
          inches.to_mi.round_2
        end
      end

  else
      # the value we are converting from is not metric
      inches = self.to_inches(from)

      # if the value we are converting to is metric, convert inches to centimeters and make the final conversion
      if(is_metric?(to))
        cm = inches.to_cm("in")
      
        if(to == "mm")
          cm.to_mm.round_2

        elsif(to == "cm")
          cm.round_2

        elsif(to == "m")
          cm.to_m.round_2

        elsif(to == "km")
          cm.to_km.round_2
        end

      # the value we are converting to is in the English system, so perform the conversion
      else
        if(to == "in")
          inches.round_2

        elsif(to == "ft")
          inches.to_ft.round_2

        elsif(to == "yd")
          inches.to_yd.round_2
          
        elsif(to == "mi")
          inches.to_mi.round_2
        end
      end
  end
end

#is_metric?(unit) ⇒ Boolean

determines if a given unit is metric

Returns:

  • (Boolean) 


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# File 'lib/metric_conversions/lengths.rb', line 9

def is_metric?(unit)
  return (unit == "mm" || unit == "cm" || unit == "m" || unit == "km")
end

#round_2 ⇒ Object

rounds a number to 2 digits



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# File 'lib/metric_conversions/lengths.rb', line 4

def round_2
  (self * 100).round / 100.0
end

#to_cm(from) ⇒ Object

given a from value, convert it to centimeters



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# File 'lib/metric_conversions/lengths.rb', line 114

def to_cm(from)
  if(from == "mm")
    self / 10.0

  elsif(from == "cm")
    self * 1.0

  elsif(from == "m")
    self * 100.0

  elsif(from == "in")
    self * 2.54

  else
    self * 100000.0

  end
end

#to_ft ⇒ Object

given inches, convert to feet



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# File 'lib/metric_conversions/lengths.rb', line 134

def to_ft
  self / 12.0
end

#to_inches(from) ⇒ Object

given a from value, convert it to inches



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# File 'lib/metric_conversions/lengths.rb', line 94

def to_inches(from)
  if(from == "ft")
    self * 12.0

  elsif(from == "yd")
    self * 36.0

  elsif(from == "mi")
    self * 12.0 * 5280

  elsif(from == "cm")
    self / 2.54

  elsif(from == "in")
    self * 1.0

  end
end

#to_km ⇒ Object

given centimeters, convert to kilometers



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# File 'lib/metric_conversions/lengths.rb', line 159

def to_km
  self / 100000.0
end

#to_m ⇒ Object

given centimeters, convert to meters



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# File 'lib/metric_conversions/lengths.rb', line 154

def to_m
  self / 100.0
end

#to_mi ⇒ Object

given inches, convert to miles



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# File 'lib/metric_conversions/lengths.rb', line 144

def to_mi
  self.to_ft / 5280.0
end

#to_mm ⇒ Object

given centimeters, convert to millimeters



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# File 'lib/metric_conversions/lengths.rb', line 149

def to_mm
  self * 10.0
end

#to_yd ⇒ Object

given inches, convert to yards



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# File 'lib/metric_conversions/lengths.rb', line 139

def to_yd
  self.to_ft / 3.0
end