Standard Library Utilities

Regex Find

Find digit groups with a standard regular expression.

regex The `.r` helper turns a string pattern into a regular expression. The example uses safe lookup methods that return an option or a finite iterator.

Regex Find

text
RegexFind.scala
Replay: real traced execution (multi-file project)
object Main {
  def main(args: Array[String]): Unit = {
    val text = "order 123 ready"
    val digits = "[0-9]+".r
    val first = digits.findFirstIn(text).getOrElse("none")
    val count = digits.findAllIn(text).toList.length

    println("first=" + first)
    println("count=" + count)
  }
}

object Main {
  def main(args: Array[String]): Unit = {
    val text = "no digits here"
    val digits = "[0-9]+".r
    val first = digits.findFirstIn(text).getOrElse("none")
    val count = digits.findAllIn(text).toList.length

    println("first=" + first)
    println("count=" + count)
  }
}

object Main {
  def main(args: Array[String]): Unit = {
    val text = "id 7 and 8"
    val digits = "[0-9]+".r
    val first = digits.findFirstIn(text).getOrElse("none")
    val count = digits.findAllIn(text).toList.length

    println("first=" + first)
    println("count=" + count)
  }
}

  1. text ← order 123 ready, digits ← [0-9]+, first ← 123, count ← 1

    1object Main {2  def main(args: Array[String]): Unit = {3    val text→ order 123 ready = "order 123 ready" //@text="no digits here", "id 7 and 8"4    val digits→ [0-9]+ = "[0-9]+".r5    val first→ 123 = digits[0-9]+.findFirstIn(textorder 123 ready).getOrElse("none")6    val count→ 1 = digits[0-9]+.findAllIn(textorder 123 ready).toList.length78    println("first=" + first123)9    println("count=" + count1)10  }11}
    outputfirst=123
count=1

  1. text ← no digits here, digits ← [0-9]+, first ← none, count ← 0

    1object Main {2  def main(args: Array[String]): Unit = {3    val text→ no digits here = "no digits here"4    val digits→ [0-9]+ = "[0-9]+".r5    val first→ none = digits[0-9]+.findFirstIn(textno digits here).getOrElse("none")6    val count→ 0 = digits[0-9]+.findAllIn(textno digits here).toList.length78    println("first=" + firstnone)9    println("count=" + count0)10  }11}
    outputfirst=none
count=0

  1. text ← id 7 and 8, digits ← [0-9]+, first ← 7, count ← 2

    1object Main {2  def main(args: Array[String]): Unit = {3    val text→ id 7 and 8 = "id 7 and 8"4    val digits→ [0-9]+ = "[0-9]+".r5    val first→ 7 = digits[0-9]+.findFirstIn(textid 7 and 8).getOrElse("none")6    val count→ 2 = digits[0-9]+.findAllIn(textid 7 and 8).toList.length78    println("first=" + first7)9    println("count=" + count2)10  }11}
    outputfirst=7
count=2