- 01Setting up (what you'll need)
- 02Your first output (println)
- 03Variables (val and var)
- 04Type annotations and basic types
- 05Branching (the if expression)
- 06Repeating (the for expression)
- 07Writing your own function
- 08Repeating (the while loop)
- 09Working with lists (List)
- 10Working with maps (Map)
- 11Classes (object orientation)
- 12case class
- 13Inheritance and traits
- 14Pattern matching (the match expression)
- 15The Option type (null safety)
- 16Higher-order functions, map and filter
- 17object (singletons)
- 18Strings and string interpolation
- 19for comprehensions
- 20[Project] Build a small inventory system
Working with lists (List)
This lesson covers the basics of Scala's list (List).
Writing List(value1, value2, ...) creates a list. Scala lists are immutable by default — once created, their contents cannot be changed.
The sample code creates val fruits = List("apple", "orange", "grape") and displays every element with for (f <- fruits).
A common early stumble is trying to "add" an element to a list. Because the list is immutable, writing fruits :+ "peach" merely returns a new list — the original fruits is unchanged.
In professional work, that immutability means several pieces of logic can work on the same data at once without unexpected overwriting, which makes programs safer.
๐งช This site can't compile or run Scala directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser โ nothing is sent anywhere).