Question

I’ve got date and time in separate fields, in yyyyMMdd and HHmmss formats respectively. To parse them I think to construct a yyyy-MM-ddTHH:mm:ss string and feed this to joda-time constructor. So I am looking to get 1-st 4 digits, then 2 digits starting from the index 5, etc. How to achieve this? List.fromString(String) (which I found here) seems to be broken.

Answer 1

Just use the substring() method on the string. Note that Scala strings behave like Java strings (with some extra methods), so anything that’s in java.lang.String can also be used on Scala strings.

val s = "20100903"
val t = s.substring(0, 4) // t will contain "2010"

(Note that the arguments are not length and starting index, but starting index (inclusive) and ending index (exclusive)).

But if this is about parsing dates, why don’t you just use java.text.SimpleDateFormat, like you would in Java?

val s = "20100903"
val fmt = new SimpleDateFormat("yyyyMMdd")
val date = fmt.parse(s)  // will give you a java.util.Date object