How to Format Strings in Scala

1. Creating a String in Scala
2. String Formatting Using the s Placeholder in Scala
3. String Formatting Using the f Placeholder in Scala
4. String Formatting Using the raw Placeholder in Scala
5. String Formatting Using the format() Function in Scala

In this tutorial, we will discuss the string formatting procedure in Scala.

A string is a sequence of characters and is an immutable data type as in Java. We can create a string using string literals and append (join) using the plus (+) operator.

After creating it, Scala provides several ways to format a string to make it more readable. In Scala, we can format the string using string interpolation.

Creating a String in Scala

We create a string by assigning it to a variable and printing it.

object MyClass {
    def main(args: Array[String]) {
        var str = "Scala String"
        print(str)
    }
}

Output:

Scala String

As we have already mentioned, a string is immutable, and modifying the string does not alter the original string. Here, we created a string and then modified it by adding a new string using the plus (+) operator.

object MyClass {
    def main(args: Array[String]) {
        var str = "Scala String"
        "Hello "+str
        print(str)
    }
}

Output:

Scala String

String Formatting Using the s Placeholder in Scala

String interpolation is the process of formatting string in Scala. It provides some keys/placeholders that we can use with the string.

We used the s placeholder with the string that allows to use of variables with the string and replace with the values during execution.

object MyClass {
    def main(args: Array[String]) {
        var a = 10
        var b = 20.5;
        println(s"value of a = $a")
        println(s"value of b = $b")
    }
}

Output:

value of a = 10
value of b = 20.5

String Formatting Using the f Placeholder in Scala

We used the f with the string that allows to use of variables with the string and replace with the values during execution. The variable must include $ with the variable.

object MyClass {
    def main(args: Array[String]) {
        var a = 10
        var b = 20.5;
        println(f"value of a = $a")
        println(f"value of b = $b")
    }
}

Output:

value of a = 10
value of b = 20.5

String Formatting Using the raw Placeholder in Scala

If you want to print a raw string that includes all the formatting symbols, then use the raw placeholder as a prefix with the string. You can clearly understand the difference between printing strings with or without this placeholder in the output.

object MyClass {
    def main(args: Array[String]) {
        var a = "Scala \tstring \n formatting"
        var b = raw"Scala \tstring \n formatting"
        println(a)
        println(b)
    }
}

Output:

Scala string
 formatting
Scala \tstring \n formatting

String Formatting Using the format() Function in Scala

Scala provides a string function format() which acts as a print() function of C. It is used to create a formatted string that you can use anywhere in your code.

object MyClass {
    def main(args: Array[String]) {
        var a = 1
        var b = 10
        var str1 = "This is %s string".format(a)
        var str2 = "This is %s string".format(b)
        println(str1)
        println(str2)
    }
}

Output:

This is 1 string
This is 10 string