date_trunc我希望在 Databricks中看到函式的源代碼。pyspark源代碼沒有回答我的問題。基本上我想知道核心發生了什么；例如，它運行regexp模式/方法還是有自己的演算法？
任何人都可以幫忙嗎？謝謝！
uj5u.com熱心網友回復：
Spark 代碼實際上是在 JVM 上運行的 Scala 代碼，盡管您可以從 Python 中使用它，并且可以在 GitHub 上找到它：https ://github.com/apache/spark
我相信您正在尋找的代碼可見于https://github.com/apache/spark/blob/b6aea1a8d99b3d99e91f7f195b23169d3d61b6a7/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils .scala#L971
def truncTimestamp(micros: Long, level: Int, zoneId: ZoneId): Long = {
// Time zone offsets have a maximum precision of seconds (see `java.time.ZoneOffset`). Hence
// truncation to microsecond, millisecond, and second can be done
// without using time zone information. This results in a performance improvement.
level match {
case TRUNC_TO_MICROSECOND => micros
case TRUNC_TO_MILLISECOND =>
micros - Math.floorMod(micros, MICROS_PER_MILLIS)
case TRUNC_TO_SECOND =>
micros - Math.floorMod(micros, MICROS_PER_SECOND)
case TRUNC_TO_MINUTE => truncToUnit(micros, zoneId, ChronoUnit.MINUTES)
case TRUNC_TO_HOUR => truncToUnit(micros, zoneId, ChronoUnit.HOURS)
case TRUNC_TO_DAY => truncToUnit(micros, zoneId, ChronoUnit.DAYS)
case _ => // Try to truncate date levels
val dDays = microsToDays(micros, zoneId)
daysToMicros(truncDate(dDays, level), zoneId)
}
}
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