string

Scala String FAQ: How can I count the number of times (occurrences) a character appears in a String?

Use the count method on the string, using a simple anonymous function, as shown in this example in the REPL:

scala> "hello world".count(_ == 'o')
res0: Int = 2

There are other ways to count the occurrences of a character in a string, but that's very simple and easy to read.

Scala collections FAQ: How can I convert a Scala array to a String?

A simple way to convert a Scala array to a String is with the mkString method of the Array class. (Although I've written "array", the same technique also works with any Scala sequence, including Array, List, Seq, ArrayBuffer, Vector, and other sequence types.)

Here's a quick array to string example using the Scala REPL:

When it comes to generating random strings with the scala.util.Random class, I haven't figured out yet how to use the nextString method. I've tried using it in several different ways, but I always get a string of question marks as output, like this:

Scala regex FAQ: How can I match a regex pattern to an entire string in Scala?

This morning I needed to write a little Scala code to make sure a String completely matches a regex pattern. I started off by creating a Scala Regex instance, and then realized the Regex class doesn't have a simple method to determine whether a String completely matches a pattern.

Scala FAQ: Does Scala have a String variable substitution syntax like Ruby?

UPDATE: If you're using Scala 2.10 or newer, see my new String interpolation in Scala 2.10 (embedding variables in strings) tutorial. If you're using Scala 2.9.x or older, continue with this article.