Home » Scala

Strings in Scala

By IncludeHelp Last updated : October 20, 2024

Scala strings

A string is a sequence of characters. In Scala, the String object is immutable. This means that the strings in Scala cannot be modified in the program. Its value given at the time of creation will remain constant throughout the program.

You can think of the string as a sequence of characters i.e. an array of characters that are "0" indexed. This means the first character has index 0, the second character has index 1, and so on. Every single character from the string can be extracted by using its index number.

Example

For example, suppose we have an array "arr" which defines some text, we can access any character by using its index number.

def arr = "Include Help is awesome"
arr(4)      // Output will be u
arr(11)     // Output will be p
arr(34)     // Output will give error array out of bond 
            // and a list of error related to that

Importing String Class

All operations on the Scala string are defined in the String class. Which can be imported from "java.lang.String".

Defining string

There are two syntaxes that can be used to define a string in Scala:

1) The object is created and a string is fed to it,

var name = "Include Help"
//or 
val name = "Include Help"  

2) The object of String type is created using specifier and then the string is fed to it,

var name : Sting = "Include Help"
//pr 
val name : Sting = "Include Help"

Example of Scala String

object MyClass {
        // A program to show implementation of scala string 
      def main(args: Array[String]) {
         var name = "Include Help"
         println("Welcome" + name)
         println("the 5th character of you name is" + name(5));
      }
   }

Output

WelcomeInclude Help
the 5th character of you name isd

Explanation

In the above example, we have created a string named name and Fed to it the value "include help". Then we have printed the string using the println() function. Also, we have printed the fifth character of the string using the index selection method of printing character values of a string that we have discussed previously in this tutorial.

There are many functions defined over the string object in the string class and We will be going through them in the next tutorial.

Formatting strings

The format() method in Scala is from the stringlike trait which holds methods for string operations. This method is used to format strings.

Example

object MyClass {
    def main(args: Array[String]) {
        var output = "%s earns %d in a month!"
        var employee_name = "Manju"
        var employee_salary = 400000
        var formatted_string = output.format(employee_name, employee_salary)   
        print(formatted_string)
    }
}

Output

Manju earns 400000 in a month!

String concatenation

String concatenation is joining two different strings to form a single one. Scala provides two methods to concatenate strings. They are:

1. concat() method
2. '+' operator

Example

object myObject {
    def main(args: Array[String]) {
        val string1 = "Scala "
        val string2 = "Programming Language"
        
        val concatString1 = string1.concat(string2)
        val concatString2 = string1 + string2
        
        println("The concatenated string (1) is " + concatString1)
        println("The concatenated string (2) is " + concatString2)
    }
}

Output

The concatenated string (1) is Scala Programming Language
The concatenated string (2) is Scala Programming Language

String interpolation

String interpolation is defining a string literal with one or more placeholders, these placeholders are to be replaced with variables or expressions while the final compilation of the result.

Example

object MyClass {
    def main(args: Array[String]) {
        var bikename = "KTM Duke 390"
        var topspeed = 185 
        var str = s"I have $bikename and it has a top speed of $topspeed "
        println(str)
    }
}

Output

I have KTM Duke 390 and it has a top speed of 185