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So far we've been building new classes and
using classes to add attributes and

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methods to our custom classes.

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Let's take a break from creating
classes though and look at a couple of

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useful functions for identifying what
kind of objects we're working with.

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So, these functions aren't necessarily
something you're going to use every day or

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even something you're gonna
wanna use all the time.

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They are, however, really handy when
you need to act a certain way or

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an object,
depending on what kind of object it is.

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If Python is duck typed,

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consider this to be how you separate
the mallards from the mandarins.

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So I'm gonna hop into Python, and

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I'm just gonna show what these do because
they're really fun and interactive.

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The first is probably the one that
you're going to use the most often.

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This function isinstance

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tells you whether or not something is
an instance of a particular class.

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And the string 'a' does
happen to be a string.

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You can use it with multiple types, too.

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So we can say, isinstance,
and let's get the float 5.2,

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and then inside of a new tuple
we can say int or float, and

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we get back True because it
is either an int or float.

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It's a float.

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We can also do isinstance 5.2,
is that a string, a boolean, or a dict?

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No, it's not.

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This also does expose a pretty fun
little fact from Python's past.

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Cuz you can do isinstance True,
and int, and it is.

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I'll leave it up to you to figure
out why or how that came about.

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The second function is issubclass,
issubclass.

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And this one tells you whether or

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not a particular class is
a subclass of another class.

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Like, isinstance,
this can also take a list of classes, or

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rather a couple of classes
to compare against.

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So, (bool, int) True issubclass(str,

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int) False, okay?

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And we can use that to check
the tree of our own classes, too.

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I'm gonna use Ctrl l here,
to clear the screen.

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And I'm gonna say from
thieves import Thief.

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And then I'm gonna say from
characters import Character.

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And then, I'm gonna say issubclass
is Thief is subclass of Character.

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True, since our Thief class
inherits from the Character class,

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our Thief is a subclass of Character,
of course you already knew that.

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The last two items are a bit less useful
but they're still good to know about.

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Firstly, we have the type function.

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Now, type can be used for
some trickier behavior, but

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let's just focus on using it to
get information about an instance.

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So I'm gonna make a new Thief, and

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remember I have to put in
the name argument now.

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And I'm going to say type for kenneth.

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And I get that kenneth is a Thief.

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Now, we already knew that, right?

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But, it's great that Python can tell us.

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The type function tells you the type
of object that an instance is.

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Generally, you'll want to use isinstance,
if you're wanting to know if I whether or

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not to work with an instance though, since
it will check the full inheritance tree.

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If I was to use this,
to find out whether or

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not kenneth was a Character,
I wouldn't know.

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I only know that kenneth is a Thief.

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Now, we've used the __init__
to control how it was created.

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Python's classes have tons
of these magic methods and

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we're gonna talk about several
of them in the next stage.

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Python classes also have a lot
of magic attributes too, and

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one of those is the class attribute.

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It'll tell you what class an instance is.

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So we can say kenneth.__class__ and
get back our thieves.Thief.

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And we can even go a step further and get
the magic name attribute off of the class.

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Kenneth.__class__.__name__, and
that tells us Thief.

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So if you wanted to write some code,
then inspect at an instance's class name,

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you could do it.

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While Python is heavily slanted toward
duck typing, where if an object quacks

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like a duck and waddles like a duck
should be considered a duck.

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I mean, if you can use a method on
an object and not get an exception,

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you should use it that way.

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It's still really handy to be able to
tell if something is an instance of

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a particular class or not.

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You'll find yourself using these functions
and attributes when you get into code

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that operates based on the type
of arguments it's working with.

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Often referred to metaprograming or
introspective programming.

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Both of those are beyond the scope of
this course, but feel free to look

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into them yourself, they're very
interesting ways of programming.

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All right, take a break if you need it,
get a snack if you're hungry,

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do code challenges and

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quizzes to cement all of this knowledge
in your head, then come back for

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the next stage where we'll get our hands
dirty with Python's built in classes.

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Ever wanted dot notation on a dictionary?