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Ruby Ruby Booleans Build a Simple Todo List Program Finding Array Items

Posted by Katriel Paige
Katriel Paige
9,260 Points

Not finding correct index?

I think I have the method right even accounting for relocating the if statements, but I may have messed up - it's still not returning the correct/expected index. Did I miss a key word somewhere?

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 find_index(name)
    index = 0
    found = false
    todo_items.index do |todo_item|
      if todo_item.name == name
        found = true
        break
      else index += 1
      end 
      if found
        return index
      else 
        return nil
      end 
    end 
  end
end
David Long
David Long
8,264 Points

Hi Katriel,

Is there more to your code? I think the issue lies with the add_items method. It does not seem to know what "TodoItem" is.

1 Answer

Ken jones
Ken jones
5,394 Points
Ken jones
Ken jones
5,394 Points

There are a few little problems with this class.

As it stands this function will never actually return the index because the logic is broken, it won't even make it through one iteration of your loop.

There are two paths that will get travelled here, lets say you pass the name of the first todo in your array as an argument. 

todo_item.name == name

This will return true. Great! Thats what we want, However, the next two lines is where things go wrong..

found = true
break

If you break at this point ruby will exit the innermost loop. Thats your todo_items loop. This stops the function going any further so it won't make it to the part where you check if found == true !

The second path is if you pass an argument that isn't the name of the first item in the array. Then you will make it to this section...

if found
  return index
else 
  return nil
end

In ruby the return statement will exit the function entirely. As you will only ever reach this part with a todo_item.name that isn't equal to name its going to exit the function and return nil.

So basically your loop will only make it through one iteration then it exits. Thats why you aren't getting the index returned.

the following should fix it up, I've refactored it slightly because refactoring is fun!

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 find_index(name)
    todo_items.each_with_index do |todo_item, index|
      if todo_item.name == name
        return index
      end
    end 
  end
end
Vladislav Trotsenko
Vladislav Trotsenko
9,291 Points

Nice, but your code is too big. No need to use .each_with_index method in this case ;)

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