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In this video we will use the scala REPL for an up and running example of Scala.
There are two ways of
creating variables in Scala.
0:00
The preferred way is by creating
a constant using the key word val.
0:03
This way of creating a variable supports
the second idea of functional programming,
0:07
as the contents of a val
cannot be changed.
0:12
Additionally, you can create
a mutable variable in Scala
0:15
by using the key word var
whose contents can be changed.
0:19
Let's see how this works in the REPL, the
interactive shell, which we can get to by
0:23
opening up a terminal in a Mac or command
prompt in Windows and typing Scala.
0:27
Let's open up the terminal
to start the Scala REPL.
0:33
REPL stands for read,
evaluate, print, and loop, and
0:37
it's very useful in
evaluating expressions.
0:41
Here, we've created
a variable name greeting.
0:53
A constant whose values cannot be changed.
0:55
Attempting to reassign
the value of variable greeting
0:58
will throw a reassignment to val error.
1:02
Let's take a look at that.
1:05
Let's take a similar approach, but
with a mutable variable this time.
1:10
We've created a variable called message,
which contains the string, hello world.
1:19
Because vars are mutable,
we can reassign its value.
1:24
In both instances,
you may have noticed two things.
1:33
First, we aren't required to provide a
semicolon at the end of the statement, and
1:37
that's because Scala supports
semicolon inference.
1:41
Second, we didn't have to
specify the parameter type.
1:45
That's because scala has a built
in type inference mechanism
1:49
which allows it to figure out what
the type of variable should be.
1:53
Although not recommended,
we can always supply the semicolon or
1:57
the type information if
we really wanted to.
2:01
Let's take a look.
2:04
Awesome, we learn how to create values and
variables in Scala.
2:12
In the next video, we will create our
first Scala app and learn about functions.
2:16
See you there!
2:21
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