R help - Mar 2010 - isdst warning when rounding a range of time data: fix or suppress?

Hi, I'm working with timeseries data. The values are every 5 seconds and
each series can last up to 4-5 days.

To generate the x-axis labels, I'm doing the following:

========================# Variable for displaying hours on the x-axis
rtime <<- as.POSIXct(round(range(timedata), "hours"))

# Variable for displaying days on the x-axis
stime <<- as.POSIXct(round(range(timedata), "days"))

# Plot the hours on the x-axis
axis.POSIXct(1, at=seq(rtime[1], rtime[2], by="hour"),
format="%H", cex.axis=.6, lwd=0, lwd.ticks=1, hadj=0.2, las=2,
tck=-0.02)

# Plot the days on the x-axis
axis.POSIXct(1, at=seq(stime[1], stime[2], by="day"),
format="%A", cex.axis=.7, line=1, lty=0, padj=-1.4)
========================
The data generated and the plots look fine. R issues a warning on the round()
function when rtime is set, though. It looks like this:
> round(range(cgmtime), "hours")
[1] "2003-11-04 14:00:00 EST" "2003-11-07 11:00:00 EST"
Warning message:
In if (isdst == -1) { :
  the condition has length > 1 and only the first element will be
used
>
Am I approaching this incorrectly? Is there another way to achieve the same
result without the warning? Or is there a way I can suppress the warning?

Thanks in advance,
Clay

Dear Clay, 
dear list,

I face the same problem when rounding POSIXct objects. Have you (or has
anybody) found an explanation meanwhile, or a way to work around this issue? 

Example:
opt<-options(digits.secs=3)
ts1<-as.POSIXct(c("2006-11-01 09:00:00.03", "2006-11-01
09:00:01",
"2006-11-01 09:00:01.0245", "2006-11-01
09:00:01.11","2006-11-01 09:00:03"),
tz="GMT")
ra1<-seq(2,6,1)
data<-data.frame(ts1,ra1)
data$lo1<-data$ts1==round.POSIXt(data$ts1,"secs") 
data

Even though in this example all results are correct, is there a chance that
incorrect results are returned?

Thanks,Phil







Clay Heaton wrote:
> 
> Hi, I'm working with timeseries data. The values are every 5 seconds
and
> each series can last up to 4-5 days.
> 
> To generate the x-axis labels, I'm doing the following:
> 
> ========================> # Variable for displaying hours on the x-axis
> rtime <<- as.POSIXct(round(range(timedata), "hours"))
> 
> # Variable for displaying days on the x-axis
> stime <<- as.POSIXct(round(range(timedata), "days"))
> 
> # Plot the hours on the x-axis
> axis.POSIXct(1, at=seq(rtime[1], rtime[2], by="hour"),
format="%H",
> cex.axis=.6, lwd=0, lwd.ticks=1, hadj=0.2, las=2, tck=-0.02)
> 
> # Plot the days on the x-axis
> axis.POSIXct(1, at=seq(stime[1], stime[2], by="day"),
format="%A",
> cex.axis=.7, line=1, lty=0, padj=-1.4)
> ========================> 
> The data generated and the plots look fine. R issues a warning on the
> round() function when rtime is set, though. It looks like this:
> 
>> round(range(cgmtime), "hours")
> [1] "2003-11-04 14:00:00 EST" "2003-11-07 11:00:00 EST"
> Warning message:
> In if (isdst == -1) { :
>   the condition has length > 1 and only the first element will be used
>>
> 
> Am I approaching this incorrectly? Is there another way to achieve the
> same result without the warning? Or is there a way I can suppress the
> warning?
> 
> Thanks in advance,
> Clay
> 
> ______________________________________________
> 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.
> 
> 
-- 
View this message in context:
http://r.789695.n4.nabble.com/isdst-warning-when-rounding-a-range-of-time-data-fix-or-suppress-tp1680540p2287574.html
Sent from the R help mailing list archive at Nabble.com.