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rubyself

In Ruby, when should you use self. in your classes?

When do you use self.property_name in Ruby?

Solution

  • Use self when calling a class's mutator. For example, this won't work:

    class Foo
  attr_writer :bar
  def do_something
    bar = 2
  end
end

    The problem is that 'bar = 2' creates a local variable named 'bar', rather than calling the method 'bar=' which was created by attr_writer. However, a little self will fix it:

    class Foo
  attr_writer :bar
  def do_something
    self.bar = 2
  end
end

    self.bar = 2 calls the method bar=, as desired.

    You may also use self to call a reader with the same name as a local variable:

    class Foo
  attr_reader :bar
  def do_something
    bar = 123
    puts self.bar
  end
end

    But it's usually better to avoid giving a local variable the same name as an accessor.