I have this dataframe:

df<-structure(list(date = structure(c(1395874800, 1395874800, 1395874800,
1395874800, 1395874800), class = c("POSIXct", "POSIXt"), tzone = ""),
     hour = structure(c(-2209121804, -2209121567, -2209121005,
     -2209118616, -2209116160), class = c("POSIXct", "POSIXt"), tzone = ""),
     s.100 = c(29L, 36L, 6L, 53L, 18L)), .Names = c("date", "hour",
"s.100"), row.names = c(NA, -5L), class = "data.frame")


and I would like to sum first two columns ("date" and "hour") so that to end up with a new column, say "date_hour", storing both the information about the "date" and the "hour" in one POSIXct object;

I have been reading that POSIXct objects are a measure of seconds from a given origin (1st Jan 1970), so that a possible solution is to tranform the column "hour" into seconds and then add it to the column "date";

but, is there a staightforward solution for accomplishing this task?
I've been trying to extract from the column "hour" the digits representing hours, minutes and seconds and transform everything into seconds but that seem to me quite cumbersome approach...

and finally, one more question: is it possible to represent hundred of seconds as given in the column "s.100" of the given dataframe within the same new POSIXct object "date_hour"?


thanksfor the support

  


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