Reference materials to help with Scala learning. We’ve collected auxiliary materials needed during the learning process, including glossary, version comparison, FAQ, and reference links.

Appendix list#

The table below lists the documents provided in the appendix. Each document is useful as a reference during learning or when you need quick information on specific topics.

Quick reference#

We’ve collected commonly used commands and code patterns in everyday Scala development.

Commonly used sbt commands

sbt is Scala’s standard build tool. The table below shows the most frequently used commands.

Common type conversions

These are frequently used type conversion patterns in Scala. Using methods that return Option like toIntOption allows safe handling by receiving None instead of exceptions on failure.

// String → Int
"42".toInt           // 42
"42".toIntOption     // Some(42)
"abc".toIntOption    // None

// Int → String
42.toString          // "42"

// Collection conversions
List(1, 2, 3).toSet  // Set(1, 2, 3)
Set(1, 2, 3).toList  // List(1, 2, 3)

Working with Option

Option is a type-safe way to use instead of null. Various methods allow elegant handling of value presence.

val maybeValue: Option[Int] = Some(42)

// Extract value
maybeValue.getOrElse(0)      // 42
maybeValue.map(_ * 2)        // Some(84)
maybeValue.filter(_ > 50)    // None
maybeValue.foreach(println)  // prints 42

// Pattern matching
maybeValue match
  case Some(v) => s"Value: $v"
  case None    => "No value"

Key collection operations

These are core operations on Scala collections. You can transform, filter, and aggregate data in functional programming style.

val nums = List(1, 2, 3, 4, 5)

nums.map(_ * 2)          // List(2, 4, 6, 8, 10)
nums.filter(_ % 2 == 0)  // List(2, 4)
nums.reduce(_ + _)       // 15
nums.foldLeft(0)(_ + _)  // 15
nums.find(_ > 3)         // Some(4)
nums.exists(_ > 3)       // true
nums.forall(_ > 0)       // true
nums.take(2)             // List(1, 2)
nums.drop(2)             // List(3, 4, 5)
nums.grouped(2).toList   // List(List(1, 2), List(3, 4), List(5))