如何在scala中通过分隔符拆分字符串？

Question

I have a string like this:

val str = "3.2.1"

And I want to do some manipulations based on it.

I will share also what I want to do and it will be nice if you can share your suggestions:

im doing automation for some website, and based on this string I need to do some actions.

So:

the first digit - I will need to choose by value: value="str[0]"

the second digit - I will need to choose by value: value="str[0]+"."+str[1]"

the third digit - I will need to choose by value: value="str[0]+"."+str[1]+"."+str[2]"

as you can see the second field i need to choose is the name firstdigit.seconddigit and the third field is firstdigit.seconddigit.thirddigit

Answer 1

You can use pattern matching for this. First create regex:

@ val pattern = """(\d+)\.(\d+)\.(\d+)""".r
pattern: util.matching.Regex = (\d+)\.(\d+)\.(\d+)

then you can use it to pattern match:

@ "3.4.342" match { case pattern(a, b, c) => println(a, b, c) } 
(3,4,342)

if you don't need all numbers you can for example do this

"1.2.0" match { case pattern(a, _, _) => println(a) }
1

if you want to for example to take just first two numbers you can do

@ val twoNumbers = "1.2.0" match { case pattern(a, b, _) => s"$a.$b" }
twoNumbers: String = "1.2"

Answer 2

Try the following:

 scala> "3.2.1".split(".")
 res0: Array[java.lang.String] = Array(string1, string2, string3)

Answer 3

This one:

object Splitter {
  def splitAndAccumulate(string: String) = {
    val s = string.split("\\.")
    s.tail.scanLeft(s.head){ case (acc, elem) =>
      acc + "." + elem
    }
  }
}

passes this test:

test("Simple"){
  val t = Splitter.splitAndAccumulate("1.2.3")

  val answers = Seq("1", "1.2", "1.2.3")

  t.zip(answers).foreach{ case (l, r) =>
    assert(l == r)
  }
}

Answer 4

Can only add to @Lukasz's answer one more variant with the values extration:

@  val pattern = """(\d+)\.(\d+)\.(\d+)""".r 
pattern: scala.util.matching.Regex = (\d+)\.(\d+)\.(\d+)

@  val pattern(firstdigit, seconddigit, thirddigit) = "3.2.1" 
firstdigit: String = "3"
seconddigit: String = "2"
thirddigit: String = "1"

This way all the values can be treated as regular val s further in the code.

Answer 5

   val str="vaquar.khan"
   val strArray=str.split("\\.")
   strArray.foreach(println)