What is the mkString() function of an array in Scala?

Overview

The mkString() function of an array is used to display all elements of an array as a string using a separator string. This method is very useful because, ordinarily, the elements will not be displayed when printing an array.

Syntax

array.mkString(separator)
Syntax for the mkString() method

Parameters

separator: This is the string we want to use and separate each of the element of our array.

Return value

The value returned is a string representation of elements present in an array.

Example

object Main extends App {
    // create some arrays
    val randomNumbers = Array(34, 2, 5, 70, 1)
    val fruits = Array("Pineapple", "Banana", "Orange")
    val cgpas : Array[Double] = Array(3.4, 4.5, 2.5, 0.5)
    // print array in normal way
    print(randomNumbers + "\n")   // [I@7e4204e2
    print(fruits + "\n")          // [Ljava.lang.String;@b7c4869
    print(cgpas)                  // [D@740d2e78
    // print with mkString()
    print("\n"+randomNumbers.mkString("-"))  // 34-2-5-70-1
    print("\n"+fruits.mkString(" "))         // Pineapple Banana Orange
    print("\n"+cgpas.mkString(","))          // 3.4,4.5,2.5,0.5
}

Explanation

  • Lines 3–5: We create some arrays.
  • Lines 8–10: We print the arrays to the console normally. However, they are printed in a way that is not understandable.
  • Lines 13–15: We use the mkString() function to print the arrays using different separators.

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