user1179942 user1179942 - 3 months ago 19
Ruby Question

How to get attributes that were defined through attr_reader or attr_accessor

Suppose I have a class

A


class A
attr_accessor :x, :y

def initialize(x,y)
@x, @y = x, y
end
end


How can I get
x
and
y
attributes without knowing how exactly they were named.

E.g.

a = A.new(5,10)
a.attributes # => [5, 10]

Answer

Use introspection, Luke!

class A
  attr_accessor :x, :y

  def initialize(*args)
    @x, @y = args
  end

  def attrs
    instance_variables.map{|ivar| instance_variable_get ivar}
  end
end

a = A.new(5,10)
a.x # => 5
a.y # => 10
a.attrs # => [5, 10]
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