- Variables 4:48
- Variables and Methods 4 objectives
- Attribute Readers 1:46
- Attribute Readers 1 objective
- Attribute Writers and Accessors 5:20
- Attribute Writers and Accessors 2 objectives
- Methods 3:31
- Methods 1 objective
- Instance Variables and Local Variables 4:54
- Instance Variables and Local Variables 4 questions
- The to_s method 2:16
- The to_s Method 1 objective
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Methods
3:31Methods are extremely useful and powerful when writing classes. A method can manipulate the data inside of an instance of a class and return or format that data in new and interesting ways.
Classes are useful for more than just
storing attributes for
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the abstraction that we're working with.
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We can write methods inside of our
classes.
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Writing methods inside of classes is
powerful, because the methods can
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apply only to the individual instance that
we're working with.
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Let's go ahead and take our Name class and
add a method to it now using Workspaces.
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So, we've got our Name class and I just
changed this to be an attr_accessor for
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a title, first name, middle and last name.
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So, we know that we're going to have all
of those different methods set for us.
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Now, we can create our own methods to work
with in classes.
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So, let's go ahead and create a method
called full_name.
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[SOUND] And what this is going to do,
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is return the first_name,
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middle_name and last_name.
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And we'll put a space in between there
too.
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[BLANK_AUDIO]
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Now instead of all of this different stuff
right here we can call name.full_name.
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Let's go ahead and run that and see what
happens.
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Okay.
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This prints out.
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Pretty much what we wanted.
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But let's put a space here.
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Okay.
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[BLANK_AUDIO]
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That looks good.
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There we go.
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The correct thing has been printed out.
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Now we can also define another method.
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We'll say full_name_with_title.
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[BLANK_AUDIO]
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And in this one we will return the title
and the space and
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we can actually just call this method
because it returns a string.
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This uses something called an implicit
return.
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Which means that the last item on the line
is going to be the return value for
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the method.
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In this case, it's a string.
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So we can use the results of that string
later.
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And it would be just like calling the
method.
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So now, we could write full_name_with_title.
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And if we run this again, we get exactly
what we were expecting.
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Now the nice thing about using classes and
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objects [NOISE] is that the variables only
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apply to that specific instance.
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So if we created, let's say we call this
one nick,
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this variable would only have access to
its internal variables.
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They are local to this variable.
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So if we run that again, we can see that
that gets printed out just like we expect,
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and this allows us to abstract that logic
away.
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And these are both fully contained and
have access only to their respective data.
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