calling ruby instance method

Question

class R
  def initialize(number)
    @number = number
  end

  attr_accessor :number
end

r = R.new(3)

r.number => 3
r.@number => syntax error
r.(@number) => undefined method call

Why can't the instance variable invoked this way?

As far as I know thanks to the attr_accessor

def number
  @number
end

So r.number method should return self.@number which is r.@number

What did I miss?

here sawa answer is perfect one way you can get the instance variable @number value r.instance_variable_get(:@number) by this way — Rajarshi Das
– Rajarshi Das, Commented Apr 8, 2016 at 9:19

sawa · Accepted Answer · 2016-04-08 09:13:27Z

4

r.number method should return self.@number which is r.@number

No. Nowhere in the definition of the number method says self.@number. It says: @number. It should return the value of @number.

@number is an instance variable, not a method. You cannot call it (like that or in any other way), you can only refer to it from an appropriate scope.

answered Apr 8, 2016 at 9:13

sawa

169k51 gold badges287 silver badges398 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Sean Magyar Over a year ago

Is there any other conventional way to get into the scope besides the getter method?

sawa Over a year ago

@SzilardMagyar instance_eval. But that defeats OOP, and is also slow. If you can use a different syntax, you can use instance_variable_get, as Rajarshi Das notes.

Collectives™ on Stack Overflow

calling ruby instance method

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related