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You have completed Build an Address Book in Ruby!
You have completed Build an Address Book in Ruby!
Preview
The first part of our address book application that we'll address is creating a class to store our contacts. Unsurprisingly, we're calling this the Contact class!
Code Samples
class Contact
attr_writer :first_name, :middle_name, :last_name
def first_name
@first_name
end
def middle_name
@middle_name
end
def last_name
@last_name
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
end
jason = Contact.new
jason.first_name = "Jason"
jason.last_name = "Seifer"
puts jason.full_name
nick = Contact.new
nick.first_name = "Nick"
nick.middle_name = "A"
nick.last_name = "Pettit"
puts nick.full_name
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[MUSIC]
0:00
Hi, I'm Jason, and welcome to
Build an Address Book with Ruby.
0:04
We're going to be building a command
line program that will let someone
0:08
put in the names and
information of all of their contacts.
0:11
Then, we'll add in the ability to go
through, and search these contacts.
0:15
We're going to create our own classes for
0:20
each different part of
the address book program.
0:22
This will encompass the address book
itself, contacts, and their information.
0:25
What we're doing is
abstracting away the logic
0:30
of these different parts of
the program into their own classes.
0:33
This is a good example of
object oriented programming.
0:37
The process of figuring out what
logic goes to what class or
0:40
object is called domain modeling.
0:44
But that's not really super
important to remember.
0:46
Now, we have to start somewhere so
we'll go ahead and start with the user or
0:49
contact class.
0:53
Go ahead and launch a workspace, and
0:55
we'll begin to create the class
which will hold our contact.
0:56
Okay, so the first class that
we're going to create for
1:00
our address book is the contact class.
1:03
The contact is going to encompass the idea
of one of the people in your address book.
1:06
So let's go ahead,
I've launched a new Ruby workspace here.
1:14
And go ahead and hit File, and New File,
and we'll name this contact.rb.
1:16
So here we are, and
now we can go ahead and create our class.
1:23
Now let's think about what
the contact is going to have.
1:32
The contact for our purposes will have
a first name, middle name and last name.
1:36
Now we're going to want to refer
to those a little bit later,
1:43
so for right now, let's go ahead and
create attribute writers for those.
1:46
And since we have the writers, let's go
ahead and create methods to read them.
2:00
So, the first_name method is going
to return the first_name variable.
2:07
The middle_name method is going to
refer to the middle_name variable,
2:12
and the last_name method is going
to refer to the last_name variable.
2:18
Now, at the bottom of this file, let's
go ahead and just create a new contact,
2:27
make sure everything is working okay,
and we'll say jason.first_name is Jason.
2:30
I don't have a middle name.
2:39
And my last name is Seifer.
2:42
And let's go ahead and
just print out that contact.
2:48
Now I'm going to click down into
the bottom console here, and
2:50
type ruby contact.rb.
2:53
Okay, we have a contact.
2:57
And let me just go ahead and put
the first_name, space, and a last_name.
3:01
And just make sure that
this is working correctly.
3:10
Okay, that looks good.
3:12
Now when we think about our address book,
3:13
we may want to refer to
a contact in different ways.
3:15
Maybe we want to print out their
full name, like we did right here.
3:21
So let's go ahead and
create a full_name method,
3:25
that will print out
the contact's full name.
3:29
And instead of actually printing it out,
let's just go ahead and
3:33
return a string of the full name.
3:37
Now if we were just returning this,
3:39
we could do first_name,
middle_name, and last_name.
3:43
Now watch what happens
if we print this out.
3:54
We'll just print Jason.full_name.
3:57
Now notice I don't have a middle initial.
4:01
So when we print this out,
there's a little space right here.
4:06
So let's go ahead and fix that.
4:10
And instead of doing this, let's go ahead
and assemble this full name in parts.
4:13
So we'll say the full_name
is equal to the first_name.
4:20
Now right here full_name is just a local
variable inside the full_name method.
4:25
It's okay to name variables the same thing
as methods when you are inside a method.
4:30
You're not gonna have any conflict.
4:36
So we've got full_name and
then we can say,
4:38
if the middle_name is nil.
4:43
If the middle name is not nil, what we'll
do is add a space to this full name.
4:51
And then add the middle_name method which
returns the variable to that full_name.
5:03
And now we can just add
the last_name onto it.
5:11
And then we just return this variable.
5:20
And we do an implicit return as
the last line of the method.
5:23
Then when we run this,
we can see that works correctly.
5:30
And let's go ahead and
try one with a middle_name.
5:36
All right.
5:56
And we run that again.
5:58
And this works correctly.
6:00
And that is a pretty good
start to our contact class.
6:02
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