Add scala notes

data-science-notes/programming/languages/scala/index.md

@@ -3,11 +3,60 @@
 ---
 
 ## Overview
-
 ---
+Scala is statically typed modern programming language. Scala allows for _both_ object-oriented and functional programming (it is **multi-paradigm**). Scala was created with the purpose of taking a concise, elegant, and type-safe approach to common programming patterns. Scala is used is many different application settings, including [Spark](https://makeuseofdata.com/programming/frameworks/apache_spark/index.html) and for Web Development. Like many other languages, Scala interoperates with other languages, specifically [Java](https://makeuseofdata.com/programming/languages/java/index.html). {cite}`scala_into`
 
 ## Basic Syntax
+### Variable Types
+In Scala, there are two types of variables and each is created differently. Immutable variables (variables that cannot be changed) are created using `val` while mutable variables (variables whose value will change) are created using using `var`. In Scala, you should use immutable variables unless your variable's value will change. An example of each type of variable is shown below:
+```scala
+val msg1 = "Hello, World!"  // immutable variable
+var msg2 = "Hello, World!" // mutable variable
+```
+If you try to reassign (change the value of) an immutable Scala variable, you will face a compiler error:
+```scala
+msg1 = "Aloha, World" // Will _not_ work!
+```
+However, mutable Scala variables can be changed:
+```scala
+msg2 = "Aloha, World" // Will work!
+```
+### Variable Type Declaration
+In Scala, you can be explict and state a variable's type or be implict and let the complier infer the variable type:
+```scala
+val x: Int = 2 // Explict
+val x = 2 // Implict
+```
+Scala suggests preferring implict assignment, which Scala says is less verbose. If you use the implict approach, Scala considers the `Int` and `Double` the default numeric types:
+```scala
+val x = 2 // An `Int`
+val x = 2.345 // A `Double`
+```
+You may use `L`, `D`, and `F` (and their lowercase verisons) to explictly specify the type of values in Scala:
+```scala
+val i = 2_000L // val i: Long = 2000
+val j = 3.14D // val j: Double = 3.14
+val k = 2.71F // val k: Float = 2.71
+```
+For really large numbers, use `BigInt` and `BigDecimal`:
+```scala
+val x = BigInt(2718281828)
+val y = BigDecimal(314159265.35)
+```
+Use `BigDecimal` for precise arithmetic, as `Double` and `Float` are approximations.
 
+In addition, Scala offers `String` and `Char` data types:
+```scala
+val msg = "Hello, World!" // A `String`
+val m = 'H' // A `Char`
+```
+For multiline string, use three double-qoutes {cite}`scala_vars`:
+```scala
+val book_title = """
+Programming in Scala:
+A Comprehensive Step-by-Step Guide
+"""
+```
 ---
 
 ## Sources
@@ -19,4 +68,4 @@
 
 ---
 
-Contributions made by our wonderful GitHub Contributors: 
+Contributions made by our wonderful GitHub Contributors: [@madisonestabrook](https://github.com/madisonestabrook)

data-science-notes/programming/languages/scala/references.bib

@@ -0,0 +1,2 @@
+@misc{scala_into, title={Introduction - A Tour of Scala}, url={https://docs.scala-lang.org/tour/tour-of-scala.html}, journal={Scala Documentation}, author={Scala Community}}
+@misc{scala_vars, title={Variables and Data Types}, url={https://docs.scala-lang.org/scala3/book/taste-vars-data-types.html}, journal={Scala Documentation}, author={Scala Community}}