Hi All,
I am attempting to work with some data from loggers. I have read in a
.csv exported from MS Access that already has my dates and times (in 24
clock format), (with StringsAsFactors=FALSE).
> head(tdata)
LogData date time
1 77.16 2008/04/24 02:00
2 61.78 2008/04/24 04:00
3 75.44 2008/04/24 06:00
4 89.43 2008/04/24 08:00
5 95.83 2008/04/24 10:00
6 96.88 2008/04/24 24:00
I wish to be able to summarise the data using the character vectors
$data and $time (daily, monthly averages, maxima of my $LogData for
example) so I am trying to get R to recognise the $date and $time
columns as valid dates and times. Using...
> tdata$date2 = as.Date(as.character(tdata$date))
I can get a new column of valid dates, but neither:
> tdata$time2= strptime(tdata$time,"%k")
Error in `$<-.data.frame`(`*tmp*`, "time2", value = list(sec = c(0, 0, :
replacement has 9 rows, data has 10
nor trying:
> tdata$time2=chron(times=as.character(tdata$time, format= "hh:mm"))
In addition: Warning messages:
1: In unpaste(times, sep = fmt$sep, fnames = fmt$periods, nfields = 3) :
wrong number of fields in entry(ies) 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
2: In convert.times(times., fmt) : NAs introduced by coercion
3: In convert.times(times., fmt) : NAs introduced by coercion
4: In convert.times(times., fmt) : NAs introduced by coercion
gives me any valid times from my time vector. the Chron documentation
doesn't mention 24 clocks, strptime neither, and the Rnews issue 1/4
with an article about time is no help... Any thoughts would be much
appreciated.
regards
Alex Anderson
James Cook University
Townsville, Australia
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