String pad example 1

string_pad1.scala

object StringUtils {
  
  implicit class RichString(s: String) {
    /**
      * Take a string and int representing the desired string length.
      * Front pads the string with a char up to the desired length
      *
      * @param l length of string
      * @param c char to pad
      * @return
      */
    def leftPad(l: Int, c: Char = '0'): String =
      if (l < s.length) {
        s
      } else {
        val zeroes: String = (1 to l).map(_ => c).mkString
        (zeroes + s).substring(s.length())
      }
  }

}

import StringUtils._

"foo".leftPad(10, 'x')  //res0: String = xxxxxxxfoo
"foo".leftPad(2)  //res1: String = foo