matching a date/timestamp with a regex

Question

I wrote the following regex to match date strings looking like:

2019/01/02 08:20:19

the regex is val reg = "([\\d]{4})/([\\d]{2})/([\\d]{2}) ([\\d]{2}).*.r"

The Scala function is:

val dateExtraction: String => Map[String, String] = {
  string: String => {
    string match {
      case reg(year, month, day, hour) =>
                 Map(YEAR -> year, MONTH -> month, DAY -> day, HOUR -> hour )
      case _  => Map(YEAR -> "", MONTH -> "", DAY -> "", HOUR -> "")
    }
  }
}
val YEAR = "YEAR"
val MONTH = "MONTH"
val DAY = "DAY"
val HOUR= "HOUR"

I want to get the year, month, day and hour from the regex. But the date above is not parsed as expected and I get a null result. Any idea how to fix this, please.

Why not use something like `val format = new java.text.SimpleDateFormat("yyyy/MM/dd HH:mm:ss") println(format.parse("2019/01/02 08:20:19"))`? — Wiktor Stribiżew, Mar 26 '19 at 10:31
You got your `.r` inside the double quotes. It should be outside. — Dima, Mar 26 '19 at 10:56

score 2 · Accepted Answer · answered Mar 26 '19 at 11:18

I would use java.time for such a problem, like:

  val input = "2019/01/02 08:20:19";
  val formatter = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss")
  val dt = LocalDateTime.from(formatter.parse(input)).atZone(ZoneId.systemDefault())

  dt.getYear() // 2019
  dt.getMonthValue() // 1
  dt.getDayOfMonth() // 2
  dt.getHour() // 8

matching a date/timestamp with a regex

1 Answers1