Converting time into number of seconds?

Question

I am using simple date format to convert the following into number of seconds

Input : 00:00:10.000 , 00:05:10.000, 01:00:23.000

Expected output : 10 seconds , 310 seconds , 3623 seconds

Below is how I am trying but it gives negative value

fun String.convertTimeIntoSeconds(): Long {
val dateFormat: DateFormat = SimpleDateFormat("HH:mm:ss.SSS")
val date = dateFormat.parse(this)
val seconds = date.time / 1000L
return seconds
}

Not Java, but if the `java.time` classes can be used, you should. SDF is (in Java) superseded — g00se, Apr 26 '23 at 10:33
I strongly recommend that you do not use `SimpleDateFormat`, neither here nor anywhere at all. It was a notorious troublemaker of a class and for that reason replaced by java.time and it `DateTimeFormatter` class about a decade ago. However neither `SimpleDateFormat` nor `DateTimeFormatter` are for parsing an amount of time. They are only for parsing (and formatting) a date and/or time of day. You need to search for how to parse a duration using java.time. There are some questions and some good answers out there. — Ole V.V., Apr 26 '23 at 12:23
It’s not very readable, but works for parsing (Java syntax): `Duration.parse("01:00:23.000".replaceFirst("^(\\d{2}):(\\d{2}):(\\d{2}\\.\\d{3})$", "PT$1H$2M$3S"))`. Yields a `Duration` of 1 hour 23 seconds. Keep the `Duration` object if you can, or use its `toSeconds` method to convert to a `long`. I first convert your string to ISO 8601 format, `PT01H00M23.000S`, because this is what `Duration.parse()` accepts. Then that class takes care of the rest. — Ole V.V., Apr 26 '23 at 12:29
(A) `Duration.between ( LocalTime.MIN , LocalTime.parse ( "00:05:10.000" ) ).toSeconds()` per [my Answer](https://stackoverflow.com/a/41453329/642706) on original Question. See [code run](https://ideone.com/s2UaUU). (B) Educate the publisher of your data about using standard [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601#Durations) formats for a duration rather than ambiguous clock-time formats. Ex: `PT5M10S`. See [Comment by Ole V.V.](https://stackoverflow.com/questions/76109678/converting-time-into-number-of-seconds/76109901#comment134227237_76109678) — Basil Bourque, Apr 27 '23 at 18:56

score 0 · Answer 1 · answered Apr 26 '23 at 10:32

fun String.convertTimeIntoSeconds(): Long {
    val dateFormat: DateFormat = SimpleDateFormat("HH:mm:ss.SSS")
    dateFormat.timeZone = TimeZone.getTimeZone("UTC") // set time zone to UTC
    val date = dateFormat.parse(this)
    val seconds = date.time / 1000L
    return seconds
}

This should work (:

score 0 · Answer 2 · answered Apr 26 '23 at 10:52

(Since posted in Java) I'd do something like:

public static String timeDigitsToSecs(String s) {
    //("HH:mm:ss.SSS" format)
    String[] atoms = s.split("[:.]");
    Duration d = Duration.ofHours(Long.parseLong(atoms[0]))
        .plusMinutes(Long.parseLong(atoms[1]))
        .plusSeconds(Long.parseLong(atoms[2]))
        .plusMillis(Long.parseLong(atoms[3]));
    return String.valueOf(d.toSeconds());
}

Converting time into number of seconds?

2 Answers2