¿Cómo creo una lista en Scala?

How do I create a list in Scala?

Syntax for defining a Scala List. val variable_name: List[type] = List(item1, item2, item3) or val variable_name = List(item1, item2, item3) A list in Scala is mostly like a Scala array. However, the Scala List is immutable and represents a linked list data structure. On the other hand, Scala array is flat and mutable.

The following are the three basic operations which can be performed on list in scala:

1. head: The first element of a list returned by head method.
2. tail: This method returns a list consisting of all elements except the first.
3. isEmpty: This method returns true if the list is empty otherwise false.

As mentioned in an above answer, the Scala List is an immutable collection. You can create an empty list with . empty[A] . Then you can use a method :+ , +: or :: in order to add element to the list.

To flatten List of List in Scala we will use the flatten method. The same flatten method can also be applied to convert sequence of sequence to a single sequence(Array, list, Vector, etc.). You can convert list of lists to list of type strings in two ways.

How to add elements to a List in Scala (List, ListBuffer)

1. Prepending elements to Scala Lists. One thing you can do when working with a Scala List is to create a new List from an existing List .
2. Use a ListBuffer when you want a “List” you can modify.
3. Scala REPL example.
4. More functional ways to work with Scala lists.

The length() method is utilized to find the length of the list. Return Type: It returns the length of the list stated.

How to delete elements from a list in Scala?

1. Using -= operator.
2. Using remove() method.
3. Using –= operator (deletes elements of another collection)

Scala Set Example

1. import scala.collection.immutable._
2. object MainObject{
3. def main(args:Array[String]){
4. val set1 = Set() // An empty set.
5. val games = Set(“Cricket”,”Football”,”Hocky”,”Golf”) // Creating a set with elements.
6. println(set1)
7. println(games)
8. }

A Seq is an Iterable that has a defined order of elements. Sequences provide a method apply() for indexing, ranging from 0 up to the length of the sequence. Seq has many subclasses including Queue, Range, List, Stack, and LinkedList. A List is a Seq that is implemented as an immutable linked list.

Create a Scala List with the List class ‘fill’ method Another convenient way to create a Scala List is with the fill method: scala> val x = List.fill (3) (“foo”) x: List [java.lang.String] = List (foo, foo, foo) As you can see, you just specify how many items you want, and the object value you want to fill each List element with.

Scala Lists are quite similar to arrays which means, all the elements of a list have the same type but there are two important differences. First, lists are immutable, which means elements of a list cannot be changed by assignment. Second, lists represent a linked list whereas arrays are flat. The type of a list that has elements…

In Scala, a list is immutable. After we create a list, we can modify the elements when creating a new list. With functions we process many elements at once. List details. Lists have many helpful properties—we can access the first element, last element, or length. No custom code is needed for these things.

The tabulate method creates a new List whose elements are created according to the function you supply. The book Programming in Scala shows how to create a List using a simple “squares” function with the tabulate method: