Get all instance variables declared in class

Question

Please help me get all instance variables declared in a class the same way instance_methods shows me all methods available in a class.

class A   attr_accessor :ab, :ac end  puts A.instance_methods  #gives ab and ac  puts A.something         #gives me @ab @ac... 

Answer 1

You can use instance_variables:

A.instance_variables 

but that’s probably not what you want, since that gets the instance variables in the class A, not an instance of that class. So you probably want:

a = A.new a.instance_variables 

But note that just calling attr_accessor doesn’t define any instance variables (it just defines methods), so there won’t be any in the instance until you set them explicitly.

a = A.new a.instance_variables #=> [] a.ab = 'foo' a.instance_variables #=> [:@ab] 

Answer 2

If you want to get all instances variables values you can try something like this :

class A   attr_accessor :foo, :bar    def context     self.instance_variables.map do |attribute|       { attribute => self.instance_variable_get(attribute) }     end   end end  a = A.new a.foo = "foo" a.bar = 42 a.context #=> [{ :@foo => "foo" }, { :@bar => 42 }]