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Phone Number Class

6:15 with Jason Seifer

In this video, we're going to create a class that will store our phone numbers.

Code Samples

Phone Number Class (phone_number.rb):

class PhoneNumber
  attr_accessor :kind, :number

  def to_s
    "#{kind}: #{number}"
  end
end

Contact Class

require "./phone_number"

class Contact
  attr_writer :first_name, :middle_name, :last_name
  attr_reader :phone_numbers

  def initialize
    @phone_numbers = []
  end

  def add_phone_number(kind, number)
    phone_number = PhoneNumber.new
    phone_number.kind = kind
    phone_number.number = number
    phone_numbers.push(phone_number)
  end

  def first_name
    @first_name
  end

  def middle_name
    @middle_name
  end

  def last_name
    @last_name
  end

  def first_last
    first_name + " " + last_name
  end

  def last_first
    last_first = last_name
    last_first += ", "
    last_first += first_name
    if !@middle_name.nil?
      last_first += " "
      last_first += middle_name.slice(0, 1)
      last_first += "."
    end
    last_first
  end

  def full_name
    full_name = first_name
    if !@middle_name.nil?
      full_name += " "
      full_name += middle_name
    end
    full_name += ' '
    full_name += last_name
    full_name
  end

  def to_s(format = 'full_name')
    case format
    when 'full_name'
      full_name
    when 'last_first'
      last_first
    when 'first'
      first_name
    when 'last'
      last_name
    else
      first_last
    end
  end

  def print_phone_numbers
    puts "Phone Numbers"
    phone_numbers.each { |phone_number| puts phone_number }
  end
end

jason = Contact.new
jason.first_name = "Jason"
jason.last_name = "Seifer"
jason.add_phone_number("Home", "123-456-7890")
jason.add_phone_number("Work", "456-789-0123")
puts jason.to_s('full_name')
jason.print_phone_numbers
  • 0:00

    Okay, so, we have our contact class all set up in here.

  • 0:04

    And if we think about that, that's great.

  • 0:06

    We can have a list of contacts,

  • 0:07

    but wouldn't we also want to enter a contact's phone number?

  • 0:13

    Yes we would.

  • 0:14

    So what we're going to do is create a class to store phone numbers.

  • 0:19

    So hit File > New.

  • 0:21

    And we'll call this class phone_number.

  • 0:25

    And we create a phone_number.rb.

  • 0:28

    Now we can create our PhoneNumber class.

  • 0:32

    And this is gonna be a really simple class.

  • 0:36

    We're not really gonna be working with phone numbers too much by themselves.

  • 0:40

    So, we're just gonna make two attribute accessors here.

  • 0:44

    The kind of phone number it is like home, work, cell.

  • 0:47

    And, we're just going to have another attribute called number which

  • 0:51

    stores the number.

  • 0:52

    So, we can use an attribute accessor for that.

  • 0:55

    We'll do one for the kind and the number.

  • 0:59

    And then since we have that,

  • 1:02

    we can go ahead and define our two string method here.

  • 1:07

    And let's just say it's the "#{kind}: #{number}".

  • 1:12

    Now, this is a pretty simple class so we're not gonna make sure it works.

  • 1:17

    It's very simple so let's go ahead and now we can add phone numbers to our contacts.

  • 1:25

    So let's go ahead and say our contact has an attribute reader for

  • 1:34

    phone numbers because a contact will be able to have more than one phone number.

  • 1:39

    But, this means that when we create our contact class and initialize it,

  • 1:48

    we'll set the phone numbers to be an empty array.

  • 1:55

    Now that we've done that, let's go ahead and create a method to add a phone number.

  • 2:00

    To our contact.

  • 2:08

    And we'll make this method take two arguments,

  • 2:12

    the kind and the number which will correspond to the different

  • 2:16

    attributes that we have In the phone_number class.

  • 2:22

    So once we do that, we'll just create a new phone_number instance.

  • 2:29

    And we'll say the phone_number.kind is the kind argument.

  • 2:35

    And the number is the number argument.

  • 2:38

    Once we have that we wanna append it to the phone numbers array.

  • 2:44

    So we can say phonenumbers.push(phone_number).

  • 2:54

    So let's go ahead and save that and makes sure it works.

  • 3:03

    I am going to take out some of these print statements because we don't need

  • 3:06

    to test that anymore.

  • 3:10

    So we're printing out the Jason contact.

  • 3:15

    And we'll say jason.add_phone_number("Home",123-456-78-

  • 3:21

    90") that is my real phone number, feel free to call me.

  • 3:31

    And let's go ahead and add another one for work

  • 3:40

    and i'll add my real work phone number here, okay.

  • 3:46

    Now lets go ahead and just inspect the Jason contact and see what it looks like.

  • 3:54

    So I'm gonna run ruby contact.rb.

  • 3:58

    And you'll see we get this method.

  • 3:59

    Uninitialized constant Contact PhoneNumber.

  • 4:04

    Now why did we get that?

  • 4:06

    Well it's because our phone number class is in a separate file.

  • 4:11

    So when we try and access a class that's in another file,

  • 4:15

    we need to tell Ruby that that exists someplace else.

  • 4:19

    Or else Ruby doesn't know where it is.

  • 4:21

    We do that using the require key word.

  • 4:28

    And then we give it the path to the file.

  • 4:30

    So we're requiring, in the same directory as this the phone number class.

  • 4:37

    I'm gonna clear my screen and run this again.

  • 4:41

    And you'll notice, now when we do the inspect here,

  • 4:46

    we've got this contact with this phone numbers

  • 4:51

    array which contains two different phone numbers.

  • 4:57

    And this is exactly what we want.

  • 4:59

    But now, let's just go ahead and

  • 5:01

    create a method to print out the phone numbers while we are at it.

  • 5:04

    So, that we don't have to inspect it each time.

  • 5:10

    Then we'll just call this method, print phone numbers.

  • 5:16

    And this is going to be really easy, since phone numbers is an array,

  • 5:19

    we can just use the each method.

  • 5:21

    And I'll say Phone Numbers right here and then, we can just loop through them

  • 5:26

    using the each method and print out all of the phone numbers.

  • 5:34

    Now remember, each will take a block with one argument.

  • 5:45

    And now we can call jason.print_phone_numbers.

  • 5:56

    Run that again.

  • 5:58

    And here we go.

  • 5:58

    Now, you might be wondering why this knows

  • 6:03

    how to print out the kind of the phone number, and then the number, itself.

  • 6:07

    Well, it's because we are calling, automatically,

  • 6:10

    the 2s method, which we defined in the phone number class.

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