Is the question 'duplicated next to each other' or 'duplicated anywhere
later'? I read it as the latter, so would use
dup <- duplicated(x$dt)
or
dup <- duplicated(x[c("Date", "time")]
Also, be very careful as Date-time values like this can be duplicated and
refer to different times on days when DST ends. E.g. there are both
"2008-10-26 02:30:00 CEST"
"2008-10-26 02:30:00 CET"
in the timezone of Germany (at least with the names my system gives me in
English).
On Sun, 16 Nov 2008, jim holtman wrote:
This should do it for you:
x <- read.table(textConnection( "Date time
Temperature
+ 1 2008-6-1 00:00:00 5
+ 2 2008-6-1 02:00:00 5
+ 3 2008-6-1 03:00:00 6
+ 4 2008-6-1 03:00:00 0
+ 5 2008-6-1 04:00:00 6
+ 6 2008-6-1 04:00:00 0
+ 7 2008-6-1 05:00:00 7
+ 8 2008-6-1 06:00:00 7"), header=TRUE)
closeAllConnections()
# create datetime
x$dt <- as.POSIXct(paste(x$Date, x$time))
# create list of duplicate values next to each other
dup <- c(FALSE, diff(x$dt) == 0)
# remove
x[!dup,]
Date time Temperature dt
1 2008-6-1 00:00:00 5 2008-06-01 00:00:00
2 2008-6-1 02:00:00 5 2008-06-01 02:00:00
3 2008-6-1 03:00:00 6 2008-06-01 03:00:00
5 2008-6-1 04:00:00 6 2008-06-01 04:00:00
7 2008-6-1 05:00:00 7 2008-06-01 05:00:00
8 2008-6-1 06:00:00 7 2008-06-01 06:00:00
On Sun, Nov 16, 2008 at 1:10 PM, Antje Nöthlich <[EMAIL PROTECTED]> wrote:
Hei R Users,
i have the following dataframe:
Datetime Temperature and many more
collumns
1 2008-6-1 00:00:00 5
2 2008-6-1 02:00:00 5
3 2008-6-1 03:00:00 6
4 2008-6-1 03:00:00 0
5 2008-6-1 04:00:00 6
6 2008-6-1 04:00:00 0
7 2008-6-1 05:00:00 7
8 2008-6-1 06:00:00 7
. . .
. . .
. . .
3000 2008-8-31 00:00:00 3
the problem is that row 3 & 4 and row 5 & 6 have the same "Datetime" value but they
differ in the values of the "Temperature" column.
Now for the whole dataframe i would like to delete rows that have the same
"Datetime" value as the prior row.
I have tried unique(dataframe), but it does not work here because the rows are
no real duplicates of each other.
thanks in advance for your help!
Antje
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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