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

Posted by Emily Coltman
Emily Coltman
Courses Plus Student 9,623 Points

Why does this say that the method does not return a boolean value when I have put "return true"?

Hi there - not sure why this doesn't work and grateful for help? Thank you!

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.include?(name)
      return true
    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
Emily Coltman
Emily Coltman
Courses Plus Student 9,623 Points

Please can I have some help with this?! Thank you :)

Myers Carpenter
Myers Carpenter
6,421 Points

You are only returning true if it's true, but you'll return nil if it's false. Do you even need an if? What does todo_items.include?(name) return?

2 Answers

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

Hi, Emily Coltman! There's two issues here.

First: your contains? method is set up to return true when it finds a match. But it also needs to be set up to return false when it doesn't find a match. The hints provided by the challenge didn't make this totally clear, so I've updated the challenge to communicate that more effectively.

Second: your contains? method won't find any matches as it is right now. I would suggest calling the find_index method within contains?. If find_index returns nil, then contains? should return false. But if find_index returns a number, then contains? should return true.

Emily Coltman
Emily Coltman
Courses Plus Student 9,623 Points

Thanks Jay - and thanks Myles!

I've tried putting both your suggestions into practice but I'm still stuck...

My code now reads:

 def contains?(name)
    if todo_items.find_index(name) != nil
      return true
    else
      return false
    end
  end

This still gives me an error message though! What am I doing wrong?! Please help :)

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

Emily Coltman you're getting close! But todo_items.find_index attempts to call a method named find_index on the array in todo_items, which doesn't have a method named find_index defined. Instead, you want to call the find_index method on the current TodoList object.

You can call another method on the current object (self) either with self.other_method or just other_method (the self. is added implicitly):

class MyClass
  def method_1
    puts "In method_1"
    # Call another method on this object
    self.method_2
    # Same as above
    method_2
  end

  def method_2
    puts "In method_2"
  end
end

object = MyClass.new
object.method_1

This outputs:

In method_1
In method_2
In method_2

So if you take todo_items. off of your call to find_index, your code should pass the challenge.

Emily Coltman
PLUS
Emily Coltman
Courses Plus Student 9,623 Points
Emily Coltman
Emily Coltman
Courses Plus Student 9,623 Points

It worked!! Yay!!

Thanks so much Jay, most grateful for your help!

Emily

Ken jones
Ken jones
5,394 Points

As a point of interest you can refactor that entire find_index method into one line by using Array#index.

like so -> 

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)
    find_index(name) != nil
  end

  def find_index(name)
    todo_items.index { |item| item.name == name }
  end
end

This will do exactly the same thing and pass the challenge :-)