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Attribute Readers

1:46 with Jason Seifer

An attribute reader allows us to access variables in a class from outside that class. This is normally code we would have to write ourselves but Ruby gives us a shortcut in the form of an attribute reader.

Code Samples

class Name
  attr_reader :first_name, :middle_name, :last_name 

  def initialize(title, first_name, middle_name, last_name)
    @title = title
    @first_name = first_name
    @midde_name = middle_name
    @last_name = last_name
  end
end
  • 0:00

    Now that we know how to create and send in attributes when working on a class,

  • 0:05

    let's go ahead and fix up our name class with the different name attributes.

  • 0:11

    Now this pattern that we see right here,

  • 0:13

    where we are setting instance variables, and then calling them later.

  • 0:19

    It's something that's done quite a bit in Ruby.

  • 0:22

    And Ruby actually gives us a shortcut for doing this exact thing.

  • 0:28

    The shortcut is using a method called attr_reader which stands for

  • 0:35

    attribute reader.

  • 0:37

    Now let's try it right here.

  • 0:41

    When we set the attribute reader as a title,

  • 0:45

    we can go down to the Title Method and take this out.

  • 0:50

    Now, if we run this program again, we should see the same thing printed.

  • 0:57

    And we do.

  • 0:58

    When we call the Adder Reader Method.

  • 1:01

    Ruby is actually writing this method for us.

  • 1:05

    It takes the name that we send in.

  • 1:07

    Which in this case is title.

  • 1:10

    And actually creates this method.

  • 1:13

    Which just returns the variable.

  • 1:18

    So we can go ahead and do that for all of our different named attributes.

  • 1:33

    Now our class just looks like this.

  • 1:37

    And let's go ahead and

  • 1:38

    run it and just make sure that everything is printed out the same way again.

  • 1:43

    And it works exactly as we expect it to.

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