How to split sentence into words separated by multiple spaces?

Question

The following code:

val sentence = "1 2  3   4".split(" ")

gives me:

Array(1, 2, "", 3, "", "", 4)

but I'd rather want to have only the words:

Array(1, 2, 3, 4)

How can I split the sentence when the words are separated by multiple spaces?

Answer 1

Use a regular expression:

scala> "1   2 3".split(" +")
res1: Array[String] = Array(1, 2, 3)

The "+" means "one or more of the previous" (previous being a space).

Better yet, if you want to split on all whitespace:

scala> "1   2 3".split("\\s+")
res2: Array[String] = Array(1, 2, 3)

(Where "\\s" is a Pattern which matches any whitespace. Look here for more examples.)

Answer 2

You can filter out the "" from the split Array.

scala> val sentence = "1 2  3   4".split(" ").filterNot(_ == "")
sentence: Array[java.lang.String] = Array(1, 2, 3, 4)

Answer 3

This regular expression \\W+ delivers (alphaunmerical) words, thus

val sentence = "1 2  3   4".split("\\W+")
sentence: Array[String] = Array(1, 2, 3, 4)

For ease of use, in Scala 2.10.* and 2.11.* consider

implicit class RichString(val s: String) extends AnyVal {
  def words = s.split("\\W+")
}

Thus,

sentence.words
res: Array[String] = Array(1, 2, 3, 4)