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Creating a list in Scala

Scala | List creation: Here, we are going to learn how to create list in Scala programming language? Here, we are discussing various ways to create lists.
Submitted by Shivang Yadav, on May 11, 2020

List in Scala

List is a collection of immutable data of the same type. It represents a LinkedList in Scala.

Creating List in Scala

There are multiple ways to create a list. They are,

1. General Java-style programming method
2. Using fill method
3. Using range method
4. Using tabulate method
5. Using lisp style of programming

1) Creating List in Java-style programming method

The general and most popular method to create a list in initializing the elements inside a curly bracket the same style is used to create the list in java, hence it is called the Java-style.

Syntax:

    val list_name = List(element1, element2,...) 

Example:

object MyObject {
    def main(args: Array[String]) {
        println("Creating a List in Java Style")
        val mylist = List(10, 20, 10, 40, 10, 20, 90, 70)
        println("Element of the list:\n" + mylist)
    }
}

Output

Creating a List in Java Style
Element of the list:
List(10, 20, 10, 40, 10, 20, 90, 70)

2) Creating a List in Scala using fill() method

If you want to create a List of multiple elements with the same data, we will use the fill() method.

Syntax:

    val list_name = List.fill(count)(element)

Here,

• count is the number of elements of the List.
• element is the element that is repeated in the list.

Example:

object MyObject {    
    def main(args: Array[String]) {
        println("Creating a List using fill method ")
        val mylist = List.fill(5)("includehelp")
        println("Element of the list:\n" + mylist)
    }
}

Output

Creating a List using fill method 
Element of the list:
List(includehelp, includehelp, includehelp, includehelp, includehelp)

3) Creating a List in Scala using range() method

If you want to create a List with elements within a given range, we will use the range() method.

Syntax:

    val list_name = List.range(start, end, step)

Here,

• start: beginning value of the range.
• end: end value of the range.
• step: the step count i.e. element to be skipped in the List.

Example:

object MyObject {    
    def main(args: Array[String]) {
        println("Creating a List using range method ")
        val mylist = List.range(10, 50, 5)
        println("Element of the list:\n" + mylist)
    }
}

Output

Creating a List using range method 
Element of the list:
List(10, 15, 20, 25, 30, 35, 40, 45)

4) Creating a List in Scala using tabulate() method

If you want to create a List with elements that are created passing a set of values to a function.

Syntax:

    val list_name = List.tabulate(count)(function)

Here,

• count is count from 0 to count passed to function.
• function on which the count elements will be passed.

Example:

object MyObject {    
    def main(args: Array[String]) {
        println("Creating a List using tabulate method")
        val mylist = List.tabulate(10)(n => n+1)
        println("Elements of the list:\n" + mylist)
    }
}

Output

Creating a List using tabulate method
Elements of the list:
List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)

5) Creating a List in Scala in Lisp style

If you want to create a List using Lisp style programming using ::.

Syntax:

    val list_name = element1 :: element2 :: Nil

Nil here is used to end the list.

Example:

object MyObject {
    def main(args: Array[String]) {
        println("Creating a List using lisp style ")
        val mylist = "BMW S1000 RR" :: "Thunderbird 350" :: "Iron 883" :: Nil
        println("Elements of the list:\n" + mylist)
    }
}

Output

Creating a List using lisp style 
Elements of the list:
List(BMW S1000 RR, Thunderbird 350, Iron 883)