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[SOUND]
[SOUND] Hey everyone.

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I'm Kenneth,
the Python teacher here at Treehouse.

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In this course I'm gonna introduce
you to one of the most powerful

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features of Python.

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But like many things that
give you great power,

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this one will give you great,
no wait, this isn't some comic book.

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This feature will give you a lot more
power and capabilities in you programming.

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But it won't suddenly make you responsible
for the safety of a major city.

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In the time you spent with
Python you probably read or

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heard that Python is an object
oriented programming language.

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But like so
much in the world of programming,

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that very descriptive name,
object oriented programming language,

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doesn't really mean all that much,
does it?

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Yet more dense programming jargon
that we just throw at people.

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All right,
let me break it down a little bit for you.

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When I was in school and

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we talked about grammar, nouns were always
defined as a person, place, or a thing.

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And on the surface level,

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that's a pretty good explanation
of an object in programming.

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If it can be described with adjectives and

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maybe it can do things with verbs,
it's an object.

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In Python though, everything is an object.

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When you've used an integer to represent
someone's age, you used an int object.

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When you stored your name in a string,
you put your name into an str object.

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And heck, when you created a function,
you actually defined a function object.

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Most of the time though, we don't need
to think about functions being objects.

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Now, before I get into some terms and
definitions, let me say this.

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Object oriented programming is a major
area of programming and program design.

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You won't understand all of it
after doing just this course.

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I've been using the school of design for
over a decade and

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I keep learning new patterns and
approaches to it all the time.

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So, if at the end of this course you still
feel a little fuzzy about it, that's fine.

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It's to be expected.

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Just like with any large topic area,
like say algebra or baking, you'll have to

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spend time researching and experimenting
with it to really get the most out of it.

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Okay, let's define a few things and
then we'll get into some coding.

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In Python,
object types like int and str and

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list are defined with
a construct known as a class.

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Instead of using def like in functions,
we use the key word class.

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Nouns have adjectives to describe them.

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Objects, or classes, have attributes.

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Attributes are very
similar to variables but

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they're defined inside of a class and
belong to that class.

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And just like nouns can do
actions by using verbs,

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classes have methods to give
them special abilities.

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Methods look just like functions,
but again, they belong to the class.

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When we use a class,

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like creating a string from a number, we
call those resulting object an instance.

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When that instance is used, like when
we change an attribute on it or call

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a method, the instance is responsible,
not the class it was instantiated from.

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There are actually some other things to
consider about attributes and methods, but

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we’ll dive into them later.

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Wow, that was a lot to take in and
we haven’t even gotten into code yet.

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You’ll get used to all of this
new vocabulary quickly though,

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because we’ll be using it
all through this course.

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For now, get settled in and read through
the teacher’s notes to make sure you’re

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comfortable with all these new words.

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There’s a bunch of code and
a vocabulary test coming your way.