How do you generate a random string like this?

Question
1 
$ perl -le '@char=("a".."z","A".."Z");$random = join "",map { $char[int rand(scalar @char)] } 0..15;print $random'
hGAHnriMJzMdnNqZ

the string was built by letters only (including either lowercase or uppercase).
what’s the easy way in scala?

2

You can use scala.util.Random to generate random characters, e.g. using nextPrintableChar. Combine it with an iterator, to generate a sequence of them and filter to further restrict which characters you want:

Iterator.continually(Random.nextPrintableChar)  //generate random characters
  .filter(_.isLetter)  // restrict to letters only
  .take(15)  // take only the required amount
  .mkString  // combine into string
1 Like
3 
scala> Iterator.continually(Random.nextPrintableChar()).filter(_.isLetter).take(16).mkString
val res20: String = RisBIniiUGLbHvLI

This is really good. thanks a lot.

4

To generate a string who contains letters only:

Iterator.continually(Random.nextPrintableChar()).filter(_.isLetter).take(16).mkString
val res28: String = HYtlLYtPHruCXARJ

To generate the string who contains numbers only:

Iterator.continually(Random.nextPrintableChar()).filter(_.isDigit).take(16).mkString
val res30: String = 8209883032775117

To generate the string who contains letters or numbers:

Iterator.continually(Random.nextPrintableChar()).filter(_.isLetterOrDigit).take(16).mkString
val res36: String = qh7TMucfNJvnfR1b

To generate the string who contains anything:

Iterator.continually(Random.nextPrintableChar()).take(16).mkString
val res37: String = VQ:|bi[69pv9x#n)

Thanks @crater2150

5

I have found another similar way:

scala> Random.alphanumeric.filter(_.isLetter).take(16).mkString
val res58: String = HFoGWtNxkCkydkMF
2 Likes
6

Ah, nice, I didn’t know about that one. If there is already a method for generating any length of characters that’s even better :slight_smile:

2 Likes