Minutes after midnight to time

Hi,

Is there a quick function that can convert minutes (seconds) after midnight
to a time?

i.e 670.93 (minutes after midnight) --> 11:10:56.**

I know it can be done by hand but I thought there must be a function for
this already.

I'm not sure what you mean by doing it by hand, but do the following do the trick for you?

# convert seconds to hours
s2h <- function(x=670.93*60) {
   h <- floor(x/3600)
   m <- floor((x - h*3600)/60)
   s <- x - h*3600 - m*60
   sprintf("%0.2d:%0.2d:%6.3f", h, m, s)

}
# convert minutes to hours
m2h <- function(x=670.93) {
   h <- floor(x/60)
   m <- floor(x - h*60)
   s <- (x - h*60 - m) * 60
   sprintf("%0.2d:%0.2d:%6.3f", h, m, s)
}

s2h() ; m2h()

[1] "11:10:55.800"
[1] "11:10:55.800"

Cheers,
Ben

Thank you.

	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Ben Tupper
Bigelow Laboratory for Ocean Sciences
60 Bigelow Drive, P.O. Box 380
East Boothbay, Maine 04544
http://www.bigelow.org

Is there a quick function that can convert minutes (seconds) after midnight
to a time?

i.e 670.93 (minutes after midnight) --> 11:10:56.**

I know it can be done by hand but I thought there must be a function for
this already.

Sort of.  There isn't really a "time-of-day" datatype in R in the way you 
are thinking about it, so naturally there are no functions associated with 
that data type. (This is actually how Excel does it also.) There is the 
difftime data type, but it does not print to your desired format.

However, you can ignore the date portion of a POSIXt type:

strftime( as.POSIXct( "1970-01-01" ) + as.difftime( 670.93, units="mins" 
), "%H:%M:%OS3" )

[1] "11:10:55.799"

However, this is not a particularly computationally efficient route to 
your goal (a large vector of minutes values converts quickly to difftime, 
and that adds quickly to the POSIXct value, but then strftime converts it 
to POSIXlt for putting pieces into the string which is not so "quick"), so 
if you are looking for "quick" execution you might want to go ahead and do 
it, as you say, "by hand".

On the other hand, I find it quite "quick" to remember how to do this, so 
in that sense it could be described as "quick".

Thank you.

	[[alternative HTML version deleted]]

Per the Posting Guide, please don't post in HTML.

---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                       Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k

Is there a quick function that can convert minutes (seconds) after midnight
to a time?

i.e 670.93 (minutes after midnight) --> 11:10:56.**

I know it can be done by hand but I thought there must be a function for
this already.

format( as.POSIXct(Sys.Date()) + 670.93*60,
        format="%H:%M:%S", tz="UCT")

[1] "11:10:55"

Thank you.

	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

David Winsemius
Alameda, CA, USA