Scala. Split line regex returns unexpected empty String

Question

Please see the example below. I create a multiline String and then try to split it. It works fine except the first line. By default split method doesn't return delimiters. So, I wonder what is so special about the beginning of the line that it returns "". And how to update the regex to avoid it.

scala> val Shakespear =
     |     """
     |       |To be,
     |       | or not
     |       |to be:
     |     """.stripMargin
Shakespear: String =
"
To be,
 or not
to be:
    "

scala> Shakespear.split("""[\s]+""")
res3: Array[String] = Array("", To, be,, or, not, to, be:)

Thanks.

Community · Accepted Answer · 2017-05-23 10:31:26Z

3

Instead of updating regex, how about trim the white spaces at both ends, and then split:

Shakespear.trim.split("\\s+")
// res22: Array[String] = Array(To, be,, or, not, to, be:)

As for why you have an empty string, you have a new line character at the beginning of the string which is also captured by \\s, and splitting on it gives you an empty string since there is nothing in front of the delimiter.

Here is the raw representation of your string (escape borrowed from here):

def escape(raw: String): String = {
    import scala.reflect.runtime.universe._
    Literal(Constant(raw)).toString
}

escape(Shakespear)
// res24: String = "\nTo be,\n or not\nto be:\n          "

If you don't want to split on new line character, use " " instead:

Shakespear.split(" ")

//res26: Array[String] =
//Array("
//To", "be,
//", or, not
//to, "be:
//")

edited May 23, 2017 at 10:31

CommunityBot

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answered May 9, 2017 at 21:53

akuiper

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