Split a string using regex or other optimized way - regex

Question

I have a very simple string of the form
YYYYMMDDHHMMSS
Basically a full date/time string. Say an example is
20170224134523
Above implies
year: 2017
month: 02
day:24
hour:13
min:45
sec:23
I want to split it so that i can have it in variables (year, month, day, hour, min, sec). This is in Scala I want to. I was thinking should I use a 6-Tuple and on the right side I will use a regex or what as the most efficient way. If I want to do it in a concise way is what I am trying to think. Little bad with regular expressions.
Can anyone help?
I may want to have each variable in the 6-tuple as option type because otherwise that will also do my sanity check? Say if any variable comes out as None, I want to throw an exception

Answer 1

java.text.SimpleDateFormat handles this kind of date parsing well.
scala> val sdf = new SimpleDateFormat("yyyyMMddkkmmss")
sdf: java.text.SimpleDateFormat = java.text.SimpleDateFormat#8e10adc0
scala> val date = sdf.parse("20170224134523")
date: java.util.Date = Fri Feb 24 13:45:23 PST 2017
You can get the date, day, hours, etc from a successful parse of the date as the API shows below.
scala> res0.get
getClass getDate getDay getHours getMinutes getMonth getSeconds getTime getTimezoneOffset getYear
Further, I'd suggest wrapping the parse call in a Try to handle the successful and unsuccessful parsing.
scala> val date = Try(sdf.parse("20170224134523"))
date: scala.util.Try[java.util.Date] = Success(Fri Feb 24 13:45:23 PST 2017)
scala> val date = Try(sdf.parse("asdf"))
date: scala.util.Try[java.util.Date] = Failure(java.text.ParseException: Unparseable date: "asdf")
Here's the same thing using the newer LocalDateTime instead of Date and it's deprecated methods.
LocalDateTime.parse("20170224134523", DateTimeFormatter.ofPattern("yMMddkkmmss"))
java.time.LocalDateTime = 2017-02-24T13:45:23

Answer 2

Because it is a date string it probably makes sense to use a dedicated date parsing library and parse to a datetime type. Fortunatly, java provides a very good one with the java.time package.
val dateTime = LocalDateTime.parse("20170224134523", DateTimeFormatter.ofPattern("yyyyMMddHHmmss"))
Which will produce a LocalDateTime object (date and time without a timezone attached). If you need more complicated string parsing you can use a DateTimeFormatterBuilder to customize the date format exactly as you need it.

Answer 3

With such a predictable format you can grab it by position using a substring function (from, to) into a date class.
The regex pattern to grab the sections as groups is:
(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})
Demo