Ruby 数组存储不同类型的跟随图

Question

我有一个函数，它将方程作为字符串数组，并且（我希望）用它们的值替换任何已知变量（puts 语句仅用于调试）：

  def replace_known_variables
    @equation_array.map! do |x|
      for known_var in @known_variables
        puts "@equation_array is initially #@equation_array"
        if known_var.full_name == x
          x = known_var.value.to_f
          puts "x is now #{x}"
        else
          x = x
          puts "x is still #{x}"
        end
      end
    end
    puts "@equation_array is now #@equation_array"
  end

这可能不是处理这种情况的“Ruby 方式”，因此欢迎任何建议，但我的问题是，当我实际运行它时，看起来 x 已正确设置，但是当一切都说完了之后，我的@equation_array 最终保存known_var（我创建的变量类）使用的类的实例，而不是我期望的字符串。在我看来 x 实际上是作为实例存储回来的。例如：

@equation_array is initially ["amperage", "*", "resistance"]
x is now 12.0
@equation_array is initially ["amperage", "*", "resistance"]
x is still 12.0
@equation_array is initially [[#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], "*", "resistance"]
x is still *
@equation_array is initially [[#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], "*", "resistance"]
x is still *
@equation_array is initially [[#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], [#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], "resistance"]
x is still resistance
@equation_array is initially [[#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], [#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], "resistance"]
x is now 2200.0
@equation_array is now [[#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], [#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">], [#<Variable:0x000001c28755c490 @abbrev="i", @full_name="amperage", @unit="A", @value="12">, #<Variable:0x000001c28745a060 @abbrev="r", @full_name="resistance", @unit="Ohms", @value="2200">]]

我已经尝试了几件事（在所有赋值中显式指定 to_ 类型，删除值保存中的 to_f ），但没有成功，而且我基本上不确定我做错了什么（除了可能是一个令人费解的问题）总体方法论）。我可以通过创建临时哈希或其他东西来解决它，但我宁愿了解我的预期流程出了什么问题。

Answer 1

“If case” 是 Ruby 中的表达式，返回结果。由于您使用了map！，它会将返回值替换为原始值。所以尝试下面的代码。

def replace_known_variables
  @equation_array.map! do |x|
    known_var = @known_variables.find { |var| var.full_name == x }
    known_var ? known_var.value.to_f : x
  end
end