Concatenating a list of strings

Question

Is there a built in method to take all of the strings in a list of strings and concatenate them in Scala? If not, how would I do this?

Ben Reich · Accepted Answer · 2015-03-27 16:15:00Z

You might be looking for mkString:

List("a", "b").mkString //"ab"

The method also takes in an argument which joins the elements:

List("a", "b").mkString(" ") //"a b"

Without this method, you could use the more primitive reduce:

List("a", "b") reduceLeft { (soFar, next) => soFar + next } List("a", "b").reduceLeft(_+_)

Or even the more primitive foldLeft:

List("a", "b").foldLeft("")(_+_) ("" /: List("a", "b"))(_+_)

elm · Accepted Answer · 2015-03-27 06:35:26Z

An additional note on mkString, you can delimit the beginning and the end of the appended strings, for instance as follows,

scala> val x = List("a","b","c") x: List[String] = List(a, b, c) scala> x.mkString("<", "-", ">") res0: String = <a-b-c>

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