Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

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

David Curtis
David Curtis
11,301 Points
Posted by David Curtis
David Curtis
11,301 Points

TodoList method contains? not working

I already found a solution here that worked so I could pass the question; however, I was wondering why my solution (code attached) didn't work.

Thanks

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)
    if @todo_items.find_index(name) =! nil
      return true
    else
      return false
    end
  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

Jeff Jacobson-Swartfager
Jeff Jacobson-Swartfager
15,419 Points
Jeff Jacobson-Swartfager
Jeff Jacobson-Swartfager
15,419 Points

It is because of your if condition:

if @todo_items.find_index(name) =! nil

There's a couple things about this line:

  1. Evaluating against not nil is unnecessary here. If .find_index(name) doesn't return true, the else block will run.
  2. Instead of running .find_index(name) on @todo_items, you want to run it on self. This is because .find_index already iterates over the todo_items array. By calling it on @todo_items, the .find_index method looks for a todo_items array to iterate over within @todo_items (which doesn't exist).

So, if you change the line to this, it will pass:

if self.find_index(name)

The complete method will be:

  def contains?(name)
    if self.find_index(name)
      return true
    else
      return false
    end
  end