如何从红宝石中的哈希值乘以？

Posted 2021-05-03

我刚刚开始研究红宝石。我有一个简单的问题。我有我的哈希exchange_rate = ["usd" => 1, "eur" => 1.2, "gbp" => 1.3]所以我想做的是，我要制作一个脚本，该脚本将计算写入率。例如，如果我想知道20欧元的美元汇率，脚本会显示给我，your exchange rate is 24USD

这是我的代码

class ExchangeRate
  def initialize (exchange_amount_id)
    @exchange_amount = exchange_amount_id
  end

  exchange_rate = ["usd" => 1, "eur" => 1.2, "gbp" => 1.3]

  def exchange ()
  end 

  classob = ExhangeRate.new(20)
  classob.exchange()
  end
end

但是我仍然想知道如何进行此计算，以显示不同货币的写入率

答案

class ExchangeRate
  def initialize (rate)
    @rate = rate
  end

  def exchange(from, to, value)
    @rate.fetch(from) / @rate.fetch(to) * value
  end
end

rate = { usd: 1, eur: 1.2, gbp: 1.3}
money = ExchangeRate.new(rate)
puts money.exchange(:eur, :usd, 20)
# you will get 24