StringBuilder in Scala

Last Updated : 29 Mar, 2019

A String object is immutable, i.e. a String cannot be changed once created. In situations where you need to perform repeated modifications to a string, we need StringBuilder class. StringBuilder is utilized to append input data to the internal buffer. We can perform numerous operations with the support of methods on the StringBuilder. This operation comprises appending data, inserting data, and removing data.
important points:

The StringBuilder class is beneficent for mutable strings to extend effectively.
The instance of StringBuilder is utilized like a String.
Strings of Scala are immutable so, when you require a mutable String then you can use StringBuilder.

Operations performed by the StringBuilder class

Appending character: This operation is helpful in appending character.
Example:

// Scala program to append 
// a character 
  
// Creating object  
object GFG 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val x = new StringBuilder("Author"); 
  
        // Appending character  
        val y = (x += 's') 
  
        // Displays the string after  
        // appending the character  
        println(y) 
    } 
} 

Output:

Authors

Here, (x += ‘ ‘) is utilized to append a character.

Appending String: This operation is helpful in appending string.
Example:

// Scala program to append 
// a String 
  
// Creating object  
object GFG 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val x = new StringBuilder("Authors"); 
  
        // Appending String  
        val y = (x ++= " of GeeksforGeeks") 
  
        // Displays the string after  
        // appending the string  
        println(y) 
  
    } 
} 

Output:

Authors of GeeksforGeeks

Here, (x ++= ‘ ‘) is utilized to append String.

Appending String representation of number: Here, the number can be of any type like Integer, Double, Long, Float, etc.
Example:

// Scala program to append 
// String representation  
// of number 
  
// Creating object  
object num 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val x = new StringBuilder("Number of Contributors : "); 
  
        // Appending String  
        // representation of number  
        val y = x.append(800) 
  
        // Displays the string after  
        // appending the number 
        println(y) 
    } 
} 

Output:

Number of Contributors : 800

Here, x.append(n) is utilized to append the String representation of the number, where ‘n’ is the number of any type.

Resetting the content of the StringBuilder: It is helpful in resetting the content by making it empty.
Example:

// Scala program to reset  
// the content 
  
// Creating object  
object GFG 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val x = new StringBuilder("Hello") 
  
        // Resetting the content  
        val y = x.clear()  
  
        // Displays empty content 
        println(y) 
    } 
} 

Output:

()

Here, x.clear() is utilized to clear the content of the StringBuilder.

Delete operation: This operation is helpful in deleting characters from the content of the StringBuilder.
Example:

// Scala program to perform  
// delete operation 
  
// Creating object  
object delete 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val q = new StringBuilder("Computer Science") 
  
        // Deleting characters  
        val r = q.delete(1, 3)  
  
        // Displaying string after  
        // deleting some characters 
        println(r) 
    } 
} 

Output:

Cputer Science

Here, q.delete(i, j) is utilized to delete the character indexed from i to (j – 1).

Insertion operation: This operation is helpful in inserting Strings.
Example:

// Scala program to perform  
// insertion operation 
  
// Creating object  
object insert 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val q = new StringBuilder("GfG CS portal") 
  
        // inserting strings  
        val r = q.insert(4, "is a " )  
  
        // Displays string after  
        // insertion of required  
        // string 
        println(r) 
    } 
} 

Output:

GfG is a CS portal

Here, q.insert(i, “s”) is utilized to insert the String (s) at index i.

Converting StringBuilder to a String: StringBuilder can be converted to a String using this operation.
Example:

// Scala program of Converting  
// StringBuilder to a String 
  
// Creating object  
object builder 
{ 
  
    // Main method 
    def main(args: Array[String]) 
    { 
  
        // Creating StringBuilder  
        val q = new StringBuilder("GeeksforGeeks") 
  
        // Applying conversion  
        // operation  
        val r = q.toString 
  
        // Displays String 
        println(r) 
    } 
} 