Class BasicTemperature::Temperature < Object

Temperature is a simple Value Object for basic temperature operations like conversions from Celsius to Fahrenhait or Kelvin etc.

Supported scales: Celsius, Fahrenheit, Kelvin and Rankine.

Creating Temperatures

A new temperature can be created in multiple ways:

• Using keyword arguments:

  Temperature.new(degrees: 0, scale: :celsius)
  

• Using positional arguments:

  Temperature.new(0, :celsius)
  

• Even more concise way using Temperature.[] (an alias of Temperature.new):

  Temperature[0, :celsius]
  

Creating Temperatures from already existing temperature objects

Sometimes it is useful to create a new temperature from already existing one.

For such cases, there are set_degrees and set_scale.

Since temperatures are Value Objects, both methods returns new instances.

Examples:

temperature = Temperature[0, :celsius]
# => 0 °C

new_temperature = temperature.set_degrees(15)
# => 15 °C

temperature = Temperature[0, :celsius]
# => 0 °C

new_temperature = temperature.set_scale(:kelvin)
# => 0 K

Conversions

Temperatures can be converted to diffirent scales.

Currently, the following scales are supported: Celsius, Fahrenheit, Kelvin and Rankine.

Temperature[20, :celsius].to_celsius
# => 20 °C

Temperature[20, :celsius].to_fahrenheit
# => 68 °F

Temperature[20, :celsius].to_kelvin
# => 293.15 K

Temperature[20, :celsius].to_rankine
# => 527.67 °R

If it is necessary to convert scale dynamically, to_scale method is available.

Temperature[20, :celsius].to_scale(scale)

All conversion formulas are taken from RapidTables.

Conversion precision: 2 accurate digits after the decimal dot.

Comparison

Temperature implements idiomatic <=> spaceship operator and mixes in Comparable module.

As a result, all methods from Comparable are available, e.g:

Temperature[20, :celsius] < Temperature[25, :celsius]
# => true

Temperature[20, :celsius] <= Temperature[25, :celsius]
# => true

Temperature[20, :celsius] == Temperature[25, :celsius]
# => false

Temperature[20, :celsius] > Temperature[25, :celsius]
# => false

Temperature[20, :celsius] >= Temperature[25, :celsius]
# => false

Temperature[20, :celsius].between?(Temperature[15, :celsius], Temperature[25, :celsius])
# => true

# Starting from Ruby 2.4.6
Temperature[20, :celsius].clamp(Temperature[20, :celsius], Temperature[25, :celsius])
# => 20 °C

Please note, if other temperature has a different scale, temperature is automatically converted to that scale before comparison.

Temperature[20, :celsius] == Temperature[293.15, :kelvin]
# => true

IMPORTANT !!!

degrees are rounded to the nearest value with a precision of 2 decimal digits before comparison.

This means the following temperatures are considered as equal:

Temperature[20.020, :celsius] == Temperature[20.024, :celsius]
# => true

Temperature[20.025, :celsius] == Temperature[20.029, :celsius]
# => true

while these ones are treated as NOT equal:

Temperature[20.024, :celsius] == Temperature[20.029, :celsius]
# => false

Math

Addition/Subtraction.

Temperature[20, :celsius] + Temperature[10, :celsius]
# => 30 °C

Temperature[20, :celsius] - Temperature[10, :celsius]
# => 10 °C

If second temperature has a different scale, first temperature is automatically converted to that scale before degrees addition/subtraction.

Temperature[283.15, :kelvin] + Temperature[10, :celsius]
# => 10 °C

Returned temperature will have the same scale as the second temperature.

It is possible to add/subtract numerics.

Temperature[20, :celsius] + 10
# => 30 °C

Temperature[20, :celsius] - 10
# => 10 °C

In such cases, returned temperature will have the same scale as the first temperature.

Also Ruby coersion mechanism is supported.

10 + Temperature[20, :celsius]
# => 30 °C

10 - Temperature[20, :celsius]
# => -10 °C

Negation

-Temperature[20, :celsius]
# => -20 °C

Queries

Temperature[0, :celsius].boil_water?
# => false

Temperature[0, :celsius].freeze_water?
# => true