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

Posted by Patrick Shushereba
Patrick Shushereba
10,911 Points

Returning the correct index in an array.

I'm trying to write this method, and the error that I get is that the find_index method is not returning the correct index. I tried using return index(name) but that didn't help me either.

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
    if todo_items.include?(name)
      return index
    else
      return nil
    end
    index += 1
  end

end

2 Answers

Amy Kang
Amy Kang
17,188 Points 
def find_index(name)
# this is the starting index of the array
    index = 0
    found = false
# Here you are iterating through each item in the array
      todo_items.each do |item|
# if the item is found, found variable is set to true
      found = true if item.name == name
# This will stop the .each method if found is set to true
      break if found
# otherwise the index will increase as you move on to the next item in the array
      index += 1
    end
# if the item is found, it will return the index, otherwise it will return nil
    if found
      return index
    else
      return nil
    end
  end

Also, the method is checking item.name against name because the name parameter being passed into the method is a string. If you just check it against the item object it will return false because the string and item object are not equal.

In order to check the item name against a string, you must specify which part of it you want to check. In this case you want to the check item's name against the name you are searching for.

Basically, item itself is an object, the name argument passed to the method is not. Therefore you must specify exactly what inside the object you are looking for: item.name

Hope that helps someone!

John Hill
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
John Hill
Front End Web Development Techdegree Graduate 35,236 Points
John Hill
.a{fill-rule:evenodd;}techdegree seal-36
John Hill
Front End Web Development Techdegree Graduate 35,236 Points

Hi there, this code comes from another forum thread, so I can't help explain why it works, but I tested it and it completes the challenge. Maybe you can look at it and see why it works, or someone else more fluent in Ruby can explain the details. 

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
Patrick Shushereba
Patrick Shushereba
10,911 Points

I follow what's going on in a broad sense. My question is why you check if item.name = name rather than just item by itself. If someone could clear that up I'd appreciate it.