Welcome to day 24 of the 49 Days of Ruby! 🎉
Today, we are going to discuss the self
. No, not yourself or myself, but rather the self
in Ruby.
What is the self
?
The self
in Ruby is a special keyword that enables you to access the current object.
What does that mean in practical terms? Let's take a look at an example:
class Coffee
def identify_me
puts self
end
end
> Coffee.new.identify_me
# => <Coffee:...>
In the case of the new Coffee
class, the method defined therein is within the context of that class. Thus, the self
is Coffee
.
Why is this useful?
There are a few reasons why understanding self
is important. We'll focus on two.
The first is disambiguation. The self
lets us know exactly where we are inside our code. No guessing required. We may be in an instance of a class, inside a class itself, or in main
, which is the name of the most top-level object.
The more we understand about where we are, the more empowered we are to write effective code.
The second is getting to write class-level methods.
Did you notice in the example above of the Coffee
class I needed to instantiate a Coffee
instance before invoking #indentify_me
?
Take a look at this:
class Coffee
def self.identify_me
puts self
end
end
By appending self
to the #identify_me
method we mark it as a class method, not an instance method. This means we can call Coffee.identify_me
directly without needing to instantiate a new Coffee
instance first.
That sums up our conversation on the self
for today! There's a lot more to discover about it. Feel free to share your learnings with the community, too!
Come back tomorrow for the next installment of 49 Days of Ruby! You can join the conversation on Twitter with the hashtag #49daysofruby.
Top comments (1)
Nice, keep going Ben! <3