dear r-helpers i've got a table that in extracts looks like this:
V1 V2 V3 V4 V5 1 01/01/1975 00:00:00 125.837 3.691 296.618 2 01/01/1975 01:00:00 124.799 3.679 281.307 3 01/01/1975 02:00:00 111.607 3.536 281.307 4 02/24/1976 11:00:00 21.602 2.555 93.893 5 02/24/1976 12:00:00 27.804 2.623 93.893 6 02/24/1976 13:00:00 26.105 2.604 114.716 7 10/18/1977 00:00:00 18.850 2.525 330.203 8 10/18/1977 01:00:00 21.561 2.555 320.465 9 10/18/1977 02:00:00 21.941 2.559 314.505 10 11/05/1978 01:00:00 24.981 2.592 310.464 11 11/05/1978 02:00:00 19.066 2.528 310.464 12 11/05/1978 03:00:00 26.198 2.605 305.749 13 06/29/1979 19:00:00 78.829 3.179 306.199 14 06/29/1979 20:00:00 92.221 3.325 306.199 15 06/29/1979 21:00:00 72.364 3.108 303.049 i need to find the annual maximun for each year in V3, V4 and V5 So that the result would be a table like this: V1 V4 1 01/01/1975 3.691 2 02/24/1976 2.623 3 10/18/1977 2.559 . . .and so on. i hope you can help me with this, thank you in advance, doerte -- ______________________________________________ R-help@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.