Adding time to POSIXct object in R

r datetime posixct
BlueTrin picture BlueTrin · Aug 12, 2012 · Viewed 72.2k times · Source

I would like to add 1 hour to a POSIXct object, but it does not support '+'.

This command:

as.POSIXct("2012/06/30","GMT") 
    + as.POSIXct(paste(event_hour, event_minute,0,":"), ,"%H:%M:$S")

returns this error:

Error in `+.POSIXt`(as.POSIXct("2012/06/30", "GMT"), as.POSIXct(paste(event_hour,  :
    binary '+' is not defined for "POSIXt" objects

How can I add a few hours to a POSIXct object ?

Answer

James picture James · Aug 12, 2012

POSIXct objects are a measure of seconds from an origin, usually the UNIX epoch (1st Jan 1970). Just add the requisite number of seconds to the object:

x <- Sys.time()
x
[1] "2012-08-12 13:33:13 BST"
x + 3*60*60 # add 3 hours
[1] "2012-08-12 16:33:13 BST"

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