从对象访问变量的名称 [英] Accessing a variable's name from an object

问题描述

给定一个对象:

object_name = "hello"

有没有办法获得变量的名称"object_name"?我需要创建一个带有变量名称和其中值的字符串，例如

is there any way to get the variable's name "object_name"? I need to create a string with the variable's name and the value in it, e.g.

"The name of the variable is 'object_name' and its value is 'hello'"

我试过了:

object_name.object_id
# => 20084556

推荐答案

def find_var(in_binding, object_id)
  name = in_binding.local_variables.find do |name|
    in_binding.local_variable_get(name).object_id == object_id
  end

  [name, in_binding.local_variable_get(name)]
end

the_answer = 42
find_var binding, the_answer.object_id # => [:the_answer, 42]

foo = 'bar'
baz = [foo]
find_var binding, baz.first.object_id # => [:foo, "bar"]

明显的失败 - 两个变量指向同一个对象.阿卡

Obvious downfall - two variables pointing to the same object. Aka

a = b = 42

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