Repeat a Character Multiple Times in Scala

1. Overview

In this tutorial, we’ll learn how to repeat a character or several characters multiple times in Scala using only the standard library.

2. Using the String Multiplication Method

The standard lib provides a very easy solution for this through the StringOps class, which provides many extension functions for Strings:

scala> "a" * 3
res0: String = aaa

scala> "abc" * 3
res1: String = abcabcabc

A very small detail is that we cannot use Chars directly here, otherwise it won’t work:

scala> 'a' * 3
res2: Int = 291

scala> 'a'.toString  * 3
res3: String = aaa

We need to convert the Char into a String, otherwise, it will implicitly convert the character into an Int and then do a normal arithmetic multiplication.

3. Using the List.fill() method

Another way to do this is using the List.fill() method:

scala> List.fill(3)('a')
res9: List[Char] = List(a, a, a)

scala> List.fill(3)('a').mkString
res10: String = aaa

scala> List.fill(3)("abc").mkString
res11: String = abcabcabc

This solution works with either Chars or Strings. It will create a List with as many repeated elements as we want. Then, we just need to convert them into a string using the List.mkString() method.

4. Conclusion

In this article, we learned how to easily repeat a given Char or String multiple times using only the Scala standard library. We leveraged both the List.fill() method and the StringOps extension method to produce a very simple one-liner solution.