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Ruby Ruby Booleans Build a Simple Todo List Program Returning Boolean Values: Part 2

Posted by yuva k
yuva k
4,410 Points

Find the value in the array results give me an error

  1. Please look at the line 14
  2. In the line 21, i dont understand why "todo_item.name == name" , why should we not mention only today_item, instead why are we using todo_item.name ?
todo_list.rb 
class TodoList
  attr_reader :name, :todo_items

  def initialize(name)
    @name = name
    @todo_items = []
  end

  def add_item(name)
    todo_items.push(TodoItem.new(name))
  end

  def contains?(name)
    todo_items.include?(name)
  end

  def find_index(name)
    index = 0
    found = false
        todo_items.each do |item|
      found = true if item.name == name
      break if found
      index += 1
    end
    if found
      return index
    else
      return nil
    end
  end
end

1 Answer

Jay McGavren
STAFF
Jay McGavren
Treehouse Teacher
Jay McGavren
Jay McGavren
Treehouse Teacher

In the line 21, i dont understand why "todo_item.name == name" , why should we not mention only today_item, instead why are we using todo_item.name ?

The TodoItem class looks like this:

class TodoItem
  attr_accessor :name
  def initialize(n)
    @name = n
  end
end

By default, a TodoItem object cannot be equal to a string; they have two different classes. So item == name would always be false. But item.name returns a string, and that can be equal to another string.

item = TodoItem.new("a")
puts item == "a" # false
puts item.name == "a" # true

Please look at the line 14

Your contains? method doesn't work for the same reason. include? goes through the TodoItem objects in todo_items, and tests whether current_item == name. That will always be false, so include? always returns false, so the challenge fails.

Instead, your contains? method should call find_index with the name that was passed to contains?. If find_index returns nil, then contains? should return false. If find_index returns a number, then contains? should return true. (Or, you can just take the return value of find_index and return that from contains?, since nil is treated as false in Ruby, and a number is treated as true.)