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Introduction to Scala

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Hello, World!

2:22 with andi mitre

In this video we will use the scala REPL for an up and running example of Scala.

Download & install Scala

Further Reading:

Value and variable declarations in Scala
Scala REPL

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    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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