Ruby Temperature House类

Question

Ruby的初学者，并构建了一个读取恒温器温度的House类。我是在正确的轨道上吗?我该如何调用该方法来更新温度？

让我们编写一些代码来模拟房屋及其恒温器的行为。对于这个挑战，您应该定义一个House类。以下是您应该建模的行为：

每个房子都有自己的当前温度，每个房子都有一个叫做update_temperature的方法！这将根据加热器或空调机是否打开来增加或降低温度。它还会将当前温度打印到屏幕上。当加热器打开时，当空调打开时，电流温度上升1个单位，电流温度下降2个单位。

你可以打开/关闭加热器，也可以打开/关闭空调。

作为额外的奖励，您可以为智能房屋添加此行为：

class House
  def initialize(current_temp, heater, air_cond)
    @current_temp = current_temp
    @heater = heater
    @air_cond = air_cond
  end

  def update_temperature!
    if @heater
      puts @current_temp += 1
    elsif @air_cond
      puts @current_temp -= 2
    end
  end
end

my_house = House.new(34, false, true)
my_house.update_temperature!

Answer 1

如果我没看错你的问题，要调用一个实例方法，首先必须创建一个该类的实例。在本例中，您有一个House类。

my_house = House.new(72, true, false)

my_house.update_temperature!

话虽如此，你的代码还是有一些问题的。

首先，在if语句中使用then通常是不好的做法。取而代之的是，您可以通过替换

if @heater then @current_temp += 1

使用

@current_temp += 1 if @heater

或

if @heater
  @current_temp += 1
end

其次，我可能会将update_temperature!方法重写为if/else语句。我会让你自己去学习。

最后，您需要向initialize方法添加一个end，以便您的initialize方法如下所示

   def initialize(current_temp, heater, air_cond)
     @current_temp = current_temp
     @heater = heater
     @air_cond = air_cond
   end

最后，我会说你应该去看看Why's Poignant Guide to Ruby。这将极大地帮助您处理一些正在处理的问题。

Answer 2

您在这里运行的是模拟。首先为物理单元安装SY gem：

gem install sy

然后，这是如何在受控环境模拟中进行的：

require 'sy' # physical units
module ControlledEnvironment
  class Air
    SPECIFIC_HEAT_CAPACITY = 1.005.kJ.kg(-1).K(-1)
    attr_accessor :volume, :temperature, :humidity, :pressure, :gas_composition
    # to simplify things, let's forget about humidity, gas compositions...

    def initialize( volume: 500.m(3),
                    temperature: SY::TRIPLE_POINT_OF_WATER + 20.K,
                    pressure: 101.3.kPa )
      @volume, @temperature, @pressure = volume, temperature, pressure
    end

    def density
      density_of_air_at_0_celsius = 1.205.kg.m(-3)
      atmospheric_pressure = 101.3.kPa
      density_of_air_at_0_celsius *
        SY::TRIPLE_POINT_OF_WATER / temperature *
        pressure / atmospheric_pressure
    end

    def heat!( energy )
      @temperature += energy / ( SPECIFIC_HEAT_CAPACITY * volume * density )
    end

    def cool!( energy ); heat -energy end
  end

  class ThermalExchanger
    attr_accessor :power_output
    attr_reader :target

    def initialize( power_output, target )
      @power_output = power_output
      @target = target
    end

    def act( delta_time, pow=power_output )
      target.heat! pow * delta_time
    end
  end

  class Heater < ThermalExchanger
    def heat!( delta_time )
      act delta_time
    end
  end

  class Cooler < ThermalExchanger
    def cool!( delta_time )
      act( delta_time, -power_output )
    end
  end
end

在设置了一个受控环境混入之后，让我们使用它来创建一个House类。

class House
  include ControlledEnvironment # including a mixin

  # a house has air, one heater, and one cooler
  attr_reader :heater, :cooler, :air

  def initialize( heater_power: 1.kW, cooler_power: 1.kW,
                  air_volume: 500.m(3) )
    @air = Air.new volume: air_volume
    @heater = Heater.new( heater_power, @air )
    @cooler = Cooler.new( cooler_power, @air )
  end

  # its temperature is defined as air temperature
  def temperature
    "#{(air.temperature - SY::TRIPLE_POINT_OF_WATER).to_f} centigrade"
  end

  # and, given current heating / cooling power settings, we can step forward in time
  def step( delta_time=1.min )
    heater.heat! delta_time
    cooler.cool! delta_time
    puts "After #{delta_time.in( :min )} minutes, the temperature is #{temperature}"
  end
end

现在我们可以玩：

house = House.new heater_power: 1.5.kW, cooler_power: 1.kW, air_volume: 1500.m(3)
house.temperature
#=> "20.0 centigrade"
house.step 1.h
#=> After 60 minutes, the temperature is 21.040302385090797 centigrade
house.step 1.h
#=> After 60 minutes, the temperature is 22.08429649473362 centigrade
house.heater.power_output = 0.kW # turn off the heater, for instance
#=> #<±Magnitude: 0.W >
house.step 30.min
#=> After 30 minutes, the temperature is 21.013285968306377 centigrade
100.times do house.step end