converting “1984-03-25 02:00:00” to POSIX gives NA

Question

While converting a vector of date-time to POSIXlt, just one particular time \"25-Mar-1984-02:00\" \"is converted to POSIXlt but returns NA! So, this row was getting omitted

Answer 1

While you don't say what your timezone is, this looks like Daylight Saving Time (DST) issue. In timezones that use DST, there will be a day where the hour "jumps" from 1:59:59.999 to 3:00:00.000. This means that any times in the 2AM hour do not exist on this day.

My guess is that 1984-03-25 02:00:00 is when DST occurs in your local timezone.