time question
On Nov 9, 2010, at 9:18 AM, Ralf B wrote:
I have this script which I use to get an epoch with accuracy of 1 second (based on R's inability to calculate millisecond-accurate timestamps -- at least I have not seen a straightforward solution :) ):
From help page for Sys.time: "Value Sys.time returns an object of class "POSIXct" (see DateTimeClasses). On almost all systems it will have sub-second accuracy: on systems conforming to POSIX 1003.1-2001 the time will be reported in microsecond increments. On Windows it increments in clock ticks (1/60 of a second) reported to millisecond accuracy." You may be misled by the output of default formats.
nowInSeconds <- as.numeric(Sys.time()) nowInMS <- nowInSeconds * 1000 print(nowInSeconds) print(as.character(nowInMS)) when running this I get the following:
nowInSeconds <- as.numeric(Sys.time()) nowInMS <- nowInSeconds * 1000 print(nowInSeconds)
[1] 1289312002
print(as.character(nowInMS))
[1] "1289312002093" I wonder where the 93 milliseconds come from. Is this a random number? A rounding error? Can somebody explain this? Best, Ralf
David Winsemius, MD West Hartford, CT