Access instance variable from outside the class

instance-variables, ruby

Solution

Yes, you can use `instance_variable_get` like this:

class Hello
  def method1
    @hello = "pavan"
  end
end

h = Hello.new
p h.instance_variable_get(:@hello) #nil
p h.method1                        #"pavan" - initialization of @hello
p h.instance_variable_get(:@hello) #"pavan"

If the variable is undefined (first call of `instance_variable_get` in my example) you get `nil`.

As Andrew mention in his comment:

You should not make this the default way you access instance variables as it violates encapsulation.

A better way is to define an accessor:

class Hello
  def method1
    @hello = "pavan"
  end
  attr_reader :hello  
end

h = Hello.new
p h.hello #nil
p h.method1                        #"pavan" - initialization of @hello
p h.hello #"pavan"

If you want another method name, you could alias the accessor: `alias :my_hello :hello`.

And if the class is not defined in your code, but in a gem: You can modify classes in your code and insert new functions to classes.

Problem

If an instance variable belongs to a class, can I access the instance variable (e.g. `@hello`) directly using the class instance? ``` class Hello def method1 @hello = "pavan" end end h = Hello.new puts h.method1 ```

Original source

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