A Scala function to get the Unix epoch time for X days ago

As a brief note today, here’s a Scala function to get the Unix epoch time for X days ago:

 * Returns a 10-digit Long (like 1585275929) representing the date/time.
 * Use it to get the time for 1 day ago, 2 days ago, etc. `0` will give
 * you the current time.
def unixEpochTimeForNumberOfDaysAgo(numDaysAgo: Int): Long = {
    import java.time._
    val numDaysAgoDateTime: LocalDateTime = LocalDateTime.now().minusDays(numDaysAgo)
    val zdt: ZonedDateTime = numDaysAgoDateTime.atZone(ZoneId.of("America/Denver"))
    val numDaysAgoDateTimeInMillis = zdt.toInstant.toEpochMilli
    val unixEpochTime = numDaysAgoDateTimeInMillis / 1000L

As shown in the comments, if you give it a 0 it will return the current epoch time. As shown by the function’s type signature, the function’s return type is a Long (which is a 64-bit two's complement integer).

Of course you can make the code shorter and better; I just wanted to show the steps in the approach using the Date/Time classes that were introduced in Java 8.