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Ruby Ruby Booleans Build a Simple Todo List Program Returning Boolean Values: Part 1

Caleb Kleveter
MOD
Caleb Kleveter
Treehouse Moderator 37,862 Points
Posted by Caleb Kleveter
Caleb Kleveter
Treehouse Moderator 37,862 Points

Returning boolean values: part 1.

The instructions for this challenge are as follows: "In the TodoList class, fill in the empty? method to return a boolean value. The empty? method should return true if there are no elements in the @todo_items array. The method should return false if there is more than one element in the @todo_items array."

When I run my code I get this error: "Bummer! The 'empty?' method returns false even when there are elements in the @todo_items array."

Here is my code:

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 empty?
    if @todo_item == nil
      return true
    else
      return false
    end
  end

end

I've tried to swap the return values around but I get this error: "Bummer! The empty? method returns false when there are no elements in the @todo_items array."

2 Answers

William Li
PLUS
William Li
Courses Plus Student 26,867 Points
William Li
William Li
Courses Plus Student 26,867 Points

In your code

  def empty?
    if @todo_item == nil
      return true
    else
      return false
    end
  end

if @todo_item == nil would always be evaluated to false, even when todo_item is an empty Array; in Ruby, empty Array does not equal to nil.

There can be many different ways to approach this problem. Here's one way to do it. You check for the length of the @todo_items array.

  def empty?
    @todo_items.length == 0
  end