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Ruby

Posted by Daniel Lake
Daniel Lake
6,595 Points

Except arguments when instantiating a variable

Hey guys,

i'm trying to write some of the stuff we did in the Ruby Track on my own and ask myself the following: When does the instantiated variable take arguments and when not? Here is the code written by Jason (just the beginning of it):

class TodoItem attr_reader :name

def initialize(name) @name = name @complete = false end

This code accepts one argument when i instantiate it. For example: item = TodoItem.new("Milk")

Here is the same spot of the code written by me:

class TodoItem attr_accessor :name, :complete

def create(name, status) @name = name if status.downcase == "complete" @complete = true else @complete = false end item = {name: @name, status: @complete}

return item

end

This code however doesn't accept the two arguments when i try to instantiate it with "item = TodoItem.new("Milk", "incomplete")

Would be great if someone could explain this to me. Thanks in advance :)

1 Answer

Galen Cook
Galen Cook
2,463 Points
Galen Cook
Galen Cook
2,463 Points

If you want to instantiate with two arguments, then you need to have an initialize method that accepts two arguments. Add this code in:

def initialize(name, status)
   @name = name
   @status = status
end

The initialize method is run every time you instantiate a class. Your code could work as is, but instead of passing two arguments upon instantiation, you would instantiate then call the create method you've defined and pass the arguments in there.

   item = ToDoItem.new
   item.create("Milk", "incomplete")
Daniel Lake
Daniel Lake
6,595 Points

Thanks for your answer. So the initialize method is just there to pass the arguments into the class? If so, I must have missed some seconds of the class :D

Galen Cook
Galen Cook
2,463 Points

That's one of the main reasons to use initialize, yes!

Daniel Lake
Daniel Lake
6,595 Points

Ah okay. So instead of naming my method "create" i'll name it "initialize" and as soon as my class gets instantiated the initialize method gets executed... hope i got that right. Anyway, thank you so much for helping me out.

Seth Reece
Seth Reece
32,867 Points
Seth Reece
Seth Reece
32,867 Points

Hi Daniel,

Just an added note for your question. In Ruby on Rails, your initialize method is just as Galen explained. Create is generally used as a POST method that saves an item in the database.