[R] order a data frame by date with orderl
Jim Holtman
jholtman at gmail.com
Wed May 16 12:18:32 CEST 2012
Is the a daylight saving time problem? Check your timezone and see when it occurred; these times might not be legal.
Sent from my iPad
On May 16, 2012, at 3:27, Benedikt Gehr <benedikt.gehr at ieu.uzh.ch> wrote:
> Hi
>
> I have a rather large data frame (>7000 rows with 28 columns) which I want
> to sort by date. Below I have a example of the data frame. The Date column
> is called DT, is a factor and looks like this:
>
> class(res.merge$DT)
> [1] "factor"
> head(res.merge$DT)
> [1] 17.3.2012 13:54:02 17.3.2012 14:00:07 17.3.2012 14:30:25 17.3.2012
> 15:01:15
> [5] 17.3.2012 15:32:14 17.3.2012 16:01:29
> 2530 Levels: 1.4.2012 00:00:52 1.4.2012 00:30:29 ... 9.5.2012 15:30:50
>
> res.merge is the data frame unordered. Now I want to order the data frame
> with:
>
> res.ordered<-res.merge[order(as.POSIXct(as.character(res.merge$DT),format="%d.%m.%Y
> %H:%M:%S")),]
>
> This works in fact, however for some reason there are always two entires
> that go at the end of the data frame for no obvious reason (see below,
> 09.05.2012 ist the most recent date). And this is the case for different
> data.frames. The two entries at the end are always 25.3.2012 02:00:xx and
> 25.3.2012 02.30.xx.
>
> Can anybody tell me what the problem is? Any help is most appreciated.
>
> Best Benedikt
>
> res.ordered[2545:2549,]
> DT Typ NOD Day_s DOW_s Time_s Long Lat
> 2547 9.5.2012 14:30:56 GPS 1893 9.5.2012 We 14:30:00 7.452218 46.43579
> 2548 9.5.2012 15:02:09 GPS 1893 9.5.2012 We 15:00:35 7.451983 46.43583
> 2549 9.5.2012 15:30:50 GPS 1893 9.5.2012 We 15:30:00 7.451973 46.43597
> 1845 25.3.2012 02:00:18 GPS 1848 25.3.2012 So 02:00:01 7.454266 46.45414
> 1846 25.3.2012 02:30:16 GPS 1848 25.3.2012 So 02:30:00 7.454413 46.45437
> Height TOF Status FO_GPS GPS_N AOT Day_e DOW_e Time_e BV Temp
> SOG
> 2547 1182.8 3 A 1 143 55 9.5.2012 We 14:30:56 3735 31
> 0.09
> 2548 1182.8 3 A 1 143 94 9.5.2012 We 15:02:09 3637 32
> 0.02
> 2549 1176.5 3 A 1 143 50 9.5.2012 We 15:30:50 3730 29
> 0.17
> 1845 1295.2 3 A 1 151 17 25.3.2012 So 02:00:18 3715 7
> 0.18
> 1846 1287.3 3 A 1 144 16 25.3.2012 So 02:30:16 3720 8
> 0.14
> Heading SAE HAE BW_2 BW_3 X..
> 2547 24.90 3.81 9.47 3666 3625 9.08
> 2548 7.86 0.51 7.17 3593 3586 9.11
> 2549 344.72 2.86 4.10 3662 3623 9.12
> 1845 335.54 3.53 5.63 3618 3618 0.81
> 1846 75.37 5.44 8.96 3618 3618 0.81
>
> --
> View this message in context: http://r.789695.n4.nabble.com/order-a-data-frame-by-date-with-order-tp4630225.html
> Sent from the R help mailing list archive at Nabble.com.
>
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