Ruby Programming Tutorial - 9 - Everything is an Object! Video Lecture

all righty guys welcome to your ninth
Ruby tutorial in in this oral I want to
talk a little bit more about objects I
know you guys are getting sick of me
talking about objects but I want to
mention something that is kind of
different than other programming
languages in Ruby almost everything is
an object now we already saw that we can
create classes in from our classes we
can create objects and we can use those
objects to access the attributes and
methods and all that good stuff but did
you know that Ruby already has some
classes and methods already built into
it before we even create anything so let
me go ahead and show you guys an example
go ahead and type into math brown like
12 plus 56 hit enter it gives us the
answer 68
okay our computer is not broken now what
you're seeing is two numbers being added
together okay
simple enough but did you know that
these numbers are actually objects in
Ruby pretty mind-blowing huh so remember
I said that every object has to come
from a class well these objects are
already built in to a class that already
came with Ruby in this class is called
fix num and you know I said that objects
have a couple things they have
attributes and they have methods well
the plus sign right here is actually a
method instead of printing stuff out on
the screen like we did in this method
right here which is what was it called
talked the job of this method is to add
two numbers together
now here's cool thing to find out what
class an object belongs to you can use
the dot class method so you know how up
here we created a class called Buckey
and we created an object Bo so say we
were programming and it was a couple
minutes later and we had that Bo object
and we forgot what class it belonged to
well in order to find out what class
this object came from just go ahead and
write the name of your object dot class
and go ahead and hit enter and it says
Bucky it's pretty much saying okay the
class that Bo belongs to is the class
Bucky
so now we can go ahead and use this
technique to figure out what class
the numbers came from sol-type any
random number like 36 and type dot class
now whenever you run the dot class
method it's going to tell us what class
this number came from and then we go
ahead and hit enter and it says fix num
in your scroll on view says fix them
where the heck did I make that well
actually fix num is a built in class
that came with Ruby already so like I
said there's already some built-in
classes and built-in methods that came
with the Ruby and these methods include
adding numbers together simple math and
some other things as well now on the
topic of built-in classes and built-in
methods I guess I might as well talk to
you guys about something called kernel
methods now kernel methods are commonly
used methods and again these are ones
out are already built into Ruby so you
know don't look for a class called
kernel or something kernel methods are
commonly used methods that any class can
use one example of this is puts now puts
is a method that we didn't write
ourselves but we get it whenever we
download Ruby now in order to write this
method we don't actually have to write
the class and then the dot and then the
method like we did whenever we actually
wrote our own methods so we don't have
to do anything like Ruby dot puts or arm
kernel dot puts although we can actually
write it like this so just remember this
whenever we have these kernel methods we
can just go ahead and write the method
name and we don't have to arm write an
object name before but I know that can
get kind of confusing that some methods
you can just write alone in other
methods that you create you have to
write the object and then a dot and then
the method name but even though that's
confusing I want to mention this before
I let you guys go in this tutorial with
kernel methods you can just go ahead and
write something like the name of the
method which is puts and some other
information like I am text on the screen
and it runs it or you can actually write
kernel
if you want and then use a dot separator
so in this case with kernel methods the
dot separator is optional so kernel puts
you can also have something like this is
also optional but unnecessary and I
think I spelled that wrong yep I did
so again with kernel methods basically
there are methods that are already
built-in in any class can use them now
with kernel methods you can just use the
method name like puts like that or you
can use the full kernel dot puts so I
know that can get kind of confusing but
I just want to mention that because if I
just skip over it then a bunch of people
are gonna you know send me hate mail and
yell at me so anyways thank you guys for
watching hopefully you understand the
fact that pretty much everything in Ruby
is an object even numbers and you also
understand something called kernel
methods which are basically built-in
methods that we can use and you can use
the optional kernel if you want to but
it's really unnecessary so anyways thank
you guys for watching don't forget to
subscribe and I'll see you guys in the
next video