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POHow to make a Ruby method to pass output parameters (change the value of referenced arguments)?
 

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  1. POHow to make a Ruby method to pass output parameters (change the value of referenced arguments)?
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    <p>I'm trying to make a method with output arguments in ruby.</p> <p>I read differents posts <a href="https://stackoverflow.com/questions/6527034/when-passing-objects-as-parameters-are-they-passed-by-reference">here</a> and <a href="https://stackoverflow.com/questions/1872110/is-ruby-pass-by-reference-or-by-value">here</a> about the discussion of wether ruby pass its arguments by-value or by-reference and</p> <p>I undersand that on a strict sens, Ruby always pass-by-value, but the value passed is actually a reference. Reason why there is so much debate on this.</p> <p>I find out that there are several ways to change the value of the referenced variable. For instance with the <strong>replace</strong> method when its an Array, a Hash or a String, or <strong>merge!</strong> when it's a hash.</p> <p>I found out that with <strong>integer</strong>, I can change and pass the value outside my method without any special method use.</p> <p><strong>My question is about other objects</strong>. For instance I want to retrieve the 'id' attribute of an object, and the object reference itself :</p> <pre><code> class RestaurantController &lt; ApplicationController def pizza_to_deliver(pizza_name, id_of_the_order, pizza) # pizza to eat pizza = Pizza.where(:name =&gt; pizza_name).first # unknown pizza return false if pizza.nil? # first customer order about this pizza id_of_the_order = Orders.where(:pizza_id =&gt; pizza.id).first true end end my_pizza_name = 'margerita' My_order_id = nil my_pizza = nil my_restaurant = RestaurantController.new if my_restauant.pizza_to_deliver(my_pizza_name, My_order_id, my_pizza) then puts "Pizza to deliver : #{my_order_id}" rex_dog.eat(my_pizza) end </code></pre> <p>How to make this works ? (order_id and my_pizza remains with nil)</p>
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