Hi Thomas, Would this work: res1=aggregate(dta[,"fcst"],by=list(basistime=dta[,"basistime"]),FUN=max) mm=match(paste(res1[,"basistime"],res1[,"x"]),paste(dta[,"basistime"],dta[,"fcst"])) dta[mm,] > dta[mm,] date basistime fcst usgs 20 2012-01-30 12:00:00 2012-01-25 15:02:00 47.9 44.5 40 2012-01-31 12:00:00 2012-01-26 15:11:00 50.4 44.2 50 2012-01-29 12:00:00 2012-01-27 01:41:00 43.8 43.8
cheers Peter > On 26. Oct 2017, at 17:07, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > > On Thu, 26 Oct 2017, Thomas Adams wrote: > >> Hi Jeff, >> Thank you for the suggestions -- I appreciate your help. Unfortunately, the >> result2 has two problems... >> (1) there are now 3 date columns (it looks like 2 cols are merged into 1 >> col) > > No, there are two date columns. Result2 includes the grouping value as a row > name (pulled from the names of the dta2list items by rbind). > >> (2) the output rows should not have any of the basistime dates repeated >> (maybe I misstated the problem); I need the max fcst value by basistime, but >> also list the date value for that row; for example: > > Then try out my code replacing > > dta2list <- split( dta2, dta2$date ) > > with > > dta2list <- split( dta2, dta2$basistime ) > > and > > %>% group_by( date ) > > with > > %>% group_by( basistime ) > > Please study how the code works and ask questions based on gaps in that > knowledge rather than how the results are not what you expected. This mailing > list is not a do-your-work-for-you coding service. Some help pages you should > look at include: > > ?rownames > ?split > ?lapply > ?do.call > ?rbind > ?group_by > ?do > > You might also find [1] helpful in general, and [2] helpful for understanding > dplyr. > > [1] H. Wickham, The Split-Apply-Combine Strategy for Data Analysis, Journal > of Statistical Software, vol. 40, no. 1, Apr. 2011. > > [2] H. Wickham and G. Grolemund, R for Data Science. OReilly UK Ltd, 2017. > URL: https://r4ds.had.co.nz. > >> basistime fcst >> 1 2012-01-25 15:02:00 47.9 >> 2 2012-01-26 15:11:00 50.4 >> 3 2012-01-27 01:41:00 46.0 >> 4 2012-01-27 10:15:00 47.3 >> 5 2012-01-27 15:15:00 47.3 >> 6 2012-01-28 14:22:00 46.2 >> 7 2012-01-29 13:33:00 45.8 >> 8 2012-01-30 14:11:00 44.8 >> 9 2012-01-31 14:24:00 43.9 >> 10 2012-02-01 14:55:00 41.1 >> 11 2012-02-02 14:56:00 38.1 >> 12 2012-02-03 14:40:00 36.2 >> 13 2012-02-04 15:01:00 34.7 >> 14 2012-02-05 15:04:00 33.1 >> 15 2012-02-06 14:37:00 32.2 >> This is very close to what I need. The basistime dates are all unique, with >> the max fcst value for the available basistime dates; but I additionally >> need the corresponding 'date' value. >> Best, >> Tom >> On Thu, Oct 26, 2017 at 1:28 AM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> >> wrote: >> Thanks for the dput... >> >> #### reproducible example of split-apply-combine ### >> >> dta <- structure(list(date = structure(c(1L, 2L, 3L, 4L, 5L, 6L, >> 7L, >> 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, >> 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, >> 19L, 20L, 21L, 22L, 23L, 24L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, >> 14L, 15L, 16L), .Label = c("2012-01-25 18:00:00", "2012-01-26 >> 00:00:00", >> "2012-01-26 06:00:00", "2012-01-26 12:00:00", "2012-01-26 >> 18:00:00", >> "2012-01-27 00:00:00", "2012-01-27 06:00:00", "2012-01-27 >> 12:00:00", >> "2012-01-27 18:00:00", "2012-01-28 00:00:00", "2012-01-28 >> 06:00:00", >> "2012-01-28 12:00:00", "2012-01-28 18:00:00", "2012-01-29 >> 00:00:00", >> "2012-01-29 06:00:00", "2012-01-29 12:00:00", "2012-01-29 >> 18:00:00", >> "2012-01-30 00:00:00", "2012-01-30 06:00:00", "2012-01-30 >> 12:00:00", >> "2012-01-30 18:00:00", "2012-01-31 00:00:00", "2012-01-31 >> 06:00:00", >> "2012-01-31 12:00:00", "2012-01-31 13:00:00", "2012-01-31 >> 18:00:00", >> "2012-02-01 00:00:00", "2012-02-01 06:00:00", "2012-02-01 >> 12:00:00", >> "2012-02-01 18:00:00", "2012-02-02 00:00:00", "2012-02-02 >> 06:00:00", >> "2012-02-02 12:00:00", "2012-02-02 18:00:00", "2012-02-03 >> 00:00:00", >> "2012-02-03 06:00:00", "2012-02-03 12:00:00", "2012-02-03 >> 18:00:00", >> "2012-02-04 00:00:00", "2012-02-04 06:00:00", "2012-02-04 >> 12:00:00", >> "2012-02-04 18:00:00", "2012-02-05 00:00:00", "2012-02-05 >> 06:00:00", >> "2012-02-05 12:00:00", "2012-02-05 18:00:00", "2012-02-06 >> 00:00:00", >> "2012-02-06 06:00:00", "2012-02-06 12:00:00", "2012-02-06 >> 18:00:00", >> "2012-02-07 00:00:00", "2012-02-07 06:00:00", "2012-02-07 >> 12:00:00", >> "2012-02-07 18:00:00", "2012-02-08 00:00:00", "2012-02-08 >> 06:00:00", >> "2012-02-08 12:00:00", "2012-02-08 18:00:00", "2012-02-09 >> 00:00:00", >> "2012-02-09 06:00:00", "2012-02-09 12:00:00", "2012-02-09 >> 18:00:00", >> "2012-02-10 00:00:00", "2012-02-10 06:00:00", "2012-02-10 >> 12:00:00", >> "2012-02-10 18:00:00", "2012-02-11 00:00:00", "2012-02-11 >> 06:00:00", >> "2012-02-11 12:00:00", "2012-02-11 18:00:00", "2012-02-12 >> 00:00:00", >> "2012-02-12 06:00:00", "2012-02-12 12:00:00", "2012-02-12 >> 18:00:00", >> "2012-02-13 00:00:00", "2012-02-13 06:00:00", "2012-02-13 >> 12:00:00", >> "2012-02-13 18:00:00", "2012-02-14 00:00:00", "2012-02-14 >> 06:00:00", >> "2012-02-14 12:00:00", "2012-02-14 18:00:00", "2012-02-15 >> 00:00:00", >> "2012-02-15 06:00:00", "2012-02-15 12:00:00", "2012-02-15 >> 18:00:00", >> "2012-02-16 00:00:00", "2012-02-16 06:00:00", "2012-02-16 >> 12:00:00", >> "2012-02-16 18:00:00", "2012-02-17 00:00:00", "2012-02-17 >> 06:00:00", >> "2012-02-17 12:00:00", "2012-02-17 18:00:00", "2012-02-18 >> 00:00:00", >> "2012-02-18 06:00:00", "2012-02-18 12:00:00", "2012-02-18 >> 18:00:00", >> "2012-02-19 00:00:00", "2012-02-19 06:00:00", "2012-02-19 >> 12:00:00", >> "2012-02-19 18:00:00", "2012-02-20 00:00:00", "2012-02-20 >> 06:00:00", >> "2012-02-20 12:00:00", "2012-02-20 18:00:00", "2012-02-21 >> 00:00:00", >> "2012-02-21 06:00:00", "2012-02-21 12:00:00", "2012-02-21 >> 18:00:00", >> "2012-02-22 00:00:00", "2012-02-22 06:00:00", "2012-02-22 >> 12:00:00", >> "2012-02-22 18:00:00", "2012-02-23 00:00:00", "2012-02-23 >> 06:00:00", >> "2012-02-23 12:00:00", "2012-02-23 18:00:00", "2012-02-24 >> 00:00:00", >> "2012-02-24 06:00:00", "2012-02-24 12:00:00", "2012-02-24 >> 18:00:00", >> "2012-02-25 00:00:00", "2012-02-25 06:00:00", "2012-02-25 >> 12:00:00", >> "2012-02-25 18:00:00", "2012-02-26 00:00:00", "2012-02-26 >> 06:00:00", >> "2012-02-26 12:00:00", "2012-02-26 18:00:00", "2012-02-27 >> 00:00:00", >> "2012-02-27 06:00:00", "2012-02-27 12:00:00", "2012-02-27 >> 18:00:00", >> "2012-02-28 00:00:00", "2012-02-28 06:00:00", "2012-02-28 >> 12:00:00", >> "2012-02-28 18:00:00", "2012-02-29 00:00:00", "2012-02-29 >> 06:00:00", >> "2012-02-29 12:00:00", "2012-02-29 18:00:00", "2012-03-01 >> 00:00:00", >> "2012-03-01 06:00:00", "2012-03-01 12:00:00", "2012-03-01 >> 18:00:00", >> "2012-03-02 00:00:00", "2012-03-02 06:00:00", "2012-03-02 >> 12:00:00", >> "2012-03-02 18:00:00", "2012-03-03 00:00:00", "2012-03-03 >> 06:00:00", >> "2012-03-03 12:00:00", "2012-03-03 18:00:00", "2012-03-04 >> 00:00:00", >> "2012-03-04 06:00:00", "2012-03-04 12:00:00", "2012-03-04 >> 18:00:00", >> "2012-03-05 00:00:00", "2012-03-05 06:00:00", "2012-03-05 >> 12:00:00", >> "2012-03-05 18:00:00", "2012-03-06 00:00:00", "2012-03-06 >> 06:00:00", >> "2012-03-06 12:00:00", "2012-03-06 18:00:00", "2012-03-07 >> 00:00:00", >> "2012-03-07 06:00:00", "2012-03-07 12:00:00", "2012-03-07 >> 18:00:00", >> "2012-03-08 00:00:00", "2012-03-08 06:00:00", "2012-03-08 >> 12:00:00", >> "2012-03-08 18:00:00", "2012-03-09 00:00:00", "2012-03-09 >> 06:00:00", >> "2012-03-09 12:00:00", "2012-03-09 18:00:00", "2012-03-10 >> 00:00:00", >> "2012-03-10 06:00:00", "2012-03-10 12:00:00", "2012-03-10 >> 18:00:00", >> "2012-03-11 00:00:00", "2012-03-11 06:00:00", "2012-03-11 >> 12:00:00", >> "2012-03-11 18:00:00", "2012-03-12 00:00:00", "2012-03-12 >> 06:00:00", >> "2012-03-12 12:00:00", "2012-03-12 18:00:00", "2012-03-13 >> 00:00:00", >> "2012-03-13 06:00:00", "2012-03-13 12:00:00", "2012-03-13 >> 18:00:00", >> "2012-03-14 00:00:00", "2012-03-14 06:00:00", "2012-03-14 >> 12:00:00", >> "2012-03-14 18:00:00", "2012-03-15 00:00:00", "2012-03-15 >> 06:00:00", >> "2012-03-15 12:00:00", "2012-03-15 18:00:00", "2012-03-16 >> 00:00:00", >> "2012-03-16 06:00:00", "2012-03-16 12:00:00", "2012-03-16 >> 18:00:00", >> "2012-03-17 00:00:00", "2012-03-17 06:00:00", "2012-03-17 >> 12:00:00", >> "2012-03-17 18:00:00", "2012-03-18 00:00:00", "2012-03-18 >> 06:00:00", >> "2012-03-18 12:00:00", "2012-03-18 18:00:00", "2012-03-19 >> 00:00:00", >> "2012-03-19 06:00:00", "2012-03-19 12:00:00", "2012-03-19 >> 18:00:00", >> "2012-03-20 00:00:00", "2012-03-20 06:00:00", "2012-03-20 >> 12:00:00", >> "2012-03-20 18:00:00", "2012-03-21 00:00:00", "2012-03-21 >> 06:00:00", >> "2012-03-21 12:00:00", "2012-03-21 18:00:00", "2012-03-22 >> 00:00:00", >> "2012-03-22 06:00:00", "2012-03-22 12:00:00", "2012-03-22 >> 18:00:00", >> "2012-03-23 00:00:00", "2012-03-23 06:00:00", "2012-03-23 >> 12:00:00", >> "2012-03-23 18:00:00", "2012-03-24 00:00:00", "2012-03-24 >> 06:00:00", >> "2012-03-24 12:00:00", "2012-03-24 18:00:00", "2012-03-25 >> 00:00:00", >> "2012-03-25 06:00:00", "2012-03-25 12:00:00", "2012-03-25 >> 18:00:00", >> "2012-03-26 00:00:00", "2012-03-26 06:00:00", "2012-03-26 >> 12:00:00", >> "2012-03-26 18:00:00", "2012-03-27 00:00:00", "2012-03-27 >> 06:00:00", >> "2012-03-27 12:00:00", "2012-03-27 18:00:00", "2012-03-28 >> 00:00:00", >> "2012-03-28 06:00:00", "2012-03-28 12:00:00", "2012-03-28 >> 18:00:00", >> "2012-03-29 00:00:00", "2012-03-29 06:00:00", "2012-03-29 >> 12:00:00", >> "2012-03-29 18:00:00", "2012-03-30 00:00:00", "2012-03-30 >> 06:00:00", >> "2012-03-30 12:00:00", "2012-03-30 18:00:00", "2012-03-31 >> 00:00:00", >> "2012-03-31 06:00:00", "2012-03-31 12:00:00", "2012-03-31 >> 18:00:00", >> "2012-04-01 00:00:00", "2012-04-01 06:00:00", "2012-04-01 >> 12:00:00", >> "2012-04-01 18:00:00", "2012-04-02 00:00:00", "2012-04-02 >> 06:00:00", >> "2012-04-02 12:00:00", "2012-04-02 18:00:00", "2012-04-03 >> 00:00:00", >> "2012-04-03 06:00:00", "2012-04-03 12:00:00", "2012-04-03 >> 18:00:00", >> "2012-04-04 00:00:00", "2012-04-04 06:00:00", "2012-04-04 >> 12:00:00", >> "2012-04-04 18:00:00", "2012-04-05 00:00:00", "2012-04-05 >> 06:00:00", >> "2012-04-05 12:00:00", "2012-04-05 18:00:00", "2012-04-06 >> 00:00:00", >> "2012-04-06 06:00:00", "2012-04-06 12:00:00", "2012-04-06 >> 18:00:00", >> "2012-04-07 00:00:00", "2012-04-07 06:00:00", "2012-04-07 >> 12:00:00", >> "2012-04-07 18:00:00", "2012-04-08 00:00:00", "2012-04-08 >> 06:00:00", >> "2012-04-08 12:00:00", "2012-04-08 18:00:00", "2012-04-09 >> 00:00:00", >> "2012-04-09 06:00:00", "2012-04-09 12:00:00", "2012-04-09 >> 18:00:00", >> "2012-04-10 00:00:00", "2012-04-10 06:00:00", "2012-04-10 >> 12:00:00", >> "2012-04-10 18:00:00", "2012-04-11 00:00:00", "2012-04-11 >> 06:00:00", >> "2012-04-11 12:00:00", "2012-04-11 18:00:00", "2012-04-12 >> 00:00:00", >> "2012-04-12 06:00:00", "2012-04-12 12:00:00", "2012-04-12 >> 18:00:00", >> "2012-04-13 00:00:00", "2012-04-13 06:00:00", "2012-04-13 >> 12:00:00", >> "2012-04-13 18:00:00", "2012-04-14 00:00:00", "2012-04-14 >> 06:00:00", >> "2012-04-14 12:00:00", "2012-04-14 18:00:00", "2012-04-15 >> 00:00:00", >> "2012-04-15 06:00:00", "2012-04-15 12:00:00", "2012-04-15 >> 18:00:00", >> "2012-04-16 00:00:00", "2012-04-16 06:00:00", "2012-04-16 >> 12:00:00", >> "2012-04-16 18:00:00", "2012-04-17 00:00:00", "2012-04-17 >> 06:00:00", >> "2012-04-17 12:00:00", "2012-04-17 18:00:00", "2012-04-18 >> 00:00:00", >> "2012-04-18 06:00:00", "2012-04-18 12:00:00", "2012-04-18 >> 18:00:00", >> "2012-04-19 00:00:00", "2012-04-19 06:00:00", "2012-04-19 >> 12:00:00", >> "2012-04-19 18:00:00", "2012-04-20 00:00:00", "2012-04-20 >> 06:00:00", >> "2012-04-20 12:00:00", "2012-04-20 18:00:00", "2012-04-21 >> 00:00:00", >> "2012-04-21 06:00:00", "2012-04-21 12:00:00", "2012-04-21 >> 18:00:00", >> "2012-04-22 00:00:00", "2012-04-22 06:00:00", "2012-04-22 >> 12:00:00", >> "2012-04-22 18:00:00", "2012-04-23 00:00:00", "2012-04-23 >> 06:00:00", >> "2012-04-23 12:00:00", "2012-04-23 18:00:00", "2012-04-24 >> 00:00:00", >> "2012-04-24 06:00:00", "2012-04-24 12:00:00", "2012-04-24 >> 18:00:00", >> "2012-04-25 00:00:00", "2012-04-25 06:00:00", "2012-04-25 >> 12:00:00", >> "2012-04-25 18:00:00", "2012-04-26 00:00:00", "2012-04-26 >> 06:00:00", >> "2012-04-26 12:00:00", "2012-04-26 18:00:00", "2012-04-27 >> 00:00:00", >> "2012-04-27 06:00:00", "2012-04-27 12:00:00", "2012-04-27 >> 18:00:00", >> "2012-04-28 00:00:00", "2012-04-28 06:00:00", "2012-04-28 >> 12:00:00", >> "2012-04-28 18:00:00", "2012-04-29 00:00:00", "2012-04-29 >> 06:00:00", >> "2012-04-29 12:00:00", "2012-04-29 18:00:00", "2012-04-30 >> 00:00:00", >> "2012-04-30 06:00:00", "2012-04-30 12:00:00", "2012-04-30 >> 18:00:00", >> "2012-05-01 00:00:00", "2012-05-01 06:00:00", "2012-05-01 >> 12:00:00", >> "2012-05-01 18:00:00", "2012-05-02 00:00:00", "2012-05-02 >> 06:00:00", >> "2012-05-02 12:00:00", "2012-05-02 18:00:00", "2012-05-03 >> 00:00:00", >> "2012-05-03 06:00:00", "2012-05-03 12:00:00", "2012-05-03 >> 18:00:00", >> "2012-05-04 00:00:00", "2012-05-04 06:00:00", "2012-05-04 >> 12:00:00", >> "2012-05-04 18:00:00", "2012-05-05 00:00:00", "2012-05-05 >> 06:00:00", >> "2012-05-05 12:00:00", "2012-05-05 18:00:00", "2012-05-06 >> 00:00:00", >> "2012-05-06 06:00:00", "2012-05-06 12:00:00", "2012-05-06 >> 18:00:00", >> "2012-05-07 00:00:00", "2012-05-07 06:00:00", "2012-05-07 >> 12:00:00", >> "2012-05-07 18:00:00", "2012-05-08 00:00:00", "2012-05-08 >> 06:00:00", >> "2012-05-08 12:00:00", "2012-05-08 18:00:00", "2012-05-09 >> 00:00:00", >> "2012-05-09 06:00:00", "2012-05-09 12:00:00", "2012-05-09 >> 18:00:00", >> "2012-05-10 00:00:00", "2012-05-10 06:00:00", "2012-05-10 >> 12:00:00", >> "2012-05-10 18:00:00", "2012-05-11 00:00:00", "2012-05-11 >> 06:00:00", >> "2012-05-11 12:00:00", "2012-05-11 18:00:00", "2012-05-12 >> 00:00:00", >> "2012-05-12 06:00:00", "2012-05-12 12:00:00", "2012-05-12 >> 18:00:00", >> "2012-05-13 00:00:00", "2012-05-13 06:00:00", "2012-05-13 >> 12:00:00", >> "2012-05-13 18:00:00", "2012-05-14 00:00:00", "2012-05-14 >> 06:00:00", >> "2012-05-14 12:00:00", "2012-05-14 18:00:00", "2012-05-15 >> 00:00:00", >> "2012-05-15 06:00:00", "2012-05-15 12:00:00", "2012-05-15 >> 18:00:00", >> "2012-05-16 00:00:00", "2012-05-16 06:00:00", "2012-05-16 >> 12:00:00", >> "2012-05-16 18:00:00", "2012-05-17 00:00:00", "2012-05-17 >> 06:00:00", >> "2012-05-17 12:00:00", "2012-05-17 18:00:00", "2012-05-18 >> 00:00:00", >> "2012-05-18 06:00:00", "2012-05-18 12:00:00", "2012-05-18 >> 18:00:00", >> "2012-05-19 00:00:00", "2012-05-19 06:00:00", "2012-05-19 >> 12:00:00", >> "2012-05-19 18:00:00", "2012-05-20 00:00:00", "2012-05-20 >> 06:00:00", >> "2012-05-20 12:00:00", "2012-05-20 18:00:00", "2012-05-21 >> 00:00:00", >> "2012-05-21 06:00:00", "2012-05-21 12:00:00", "2012-05-21 >> 18:00:00", >> "2012-05-22 00:00:00", "2012-05-22 06:00:00", "2012-05-22 >> 12:00:00", >> "2012-05-22 18:00:00", "2012-05-23 00:00:00", "2012-05-23 >> 06:00:00", >> "2012-05-23 12:00:00", "2012-05-23 18:00:00", "2012-05-24 >> 00:00:00", >> "2012-05-24 06:00:00", "2012-05-24 12:00:00", "2012-05-24 >> 18:00:00", >> "2012-05-25 00:00:00", "2012-05-25 06:00:00", "2012-05-25 >> 12:00:00", >> "2012-05-25 18:00:00", "2012-05-26 00:00:00", "2012-05-26 >> 06:00:00", >> "2012-05-26 12:00:00", "2012-05-26 18:00:00", "2012-05-27 >> 00:00:00", >> "2012-05-27 06:00:00", "2012-05-27 12:00:00", "2012-05-27 >> 18:00:00", >> "2012-05-28 00:00:00", "2012-05-28 06:00:00", "2012-05-28 >> 12:00:00", >> "2012-05-28 18:00:00", "2012-05-29 00:00:00", "2012-05-29 >> 06:00:00", >> "2012-05-29 12:00:00"), class = "factor"), basistime = >> structure(c(1L, >> 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, >> 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, >> 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, >> 3L), .Label = c("2012-01-25 15:02:00", "2012-01-26 15:11:00", >> "2012-01-27 01:41:00", "2012-01-27 10:15:00", "2012-01-27 >> 15:15:00", >> "2012-01-28 14:22:00", "2012-01-29 13:33:00", "2012-01-30 >> 14:11:00", >> "2012-01-31 14:24:00", "2012-02-01 14:55:00", "2012-02-02 >> 14:56:00", >> "2012-02-03 14:40:00", "2012-02-04 15:01:00", "2012-02-05 >> 15:04:00", >> "2012-02-06 14:37:00", "2012-02-07 14:42:00", "2012-02-08 >> 14:44:00", >> "2012-02-09 14:27:00", "2012-02-10 14:33:00", "2012-02-11 >> 15:05:00", >> "2012-02-12 15:09:00", "2012-02-13 15:00:00", "2012-02-14 >> 15:10:00", >> "2012-02-15 14:46:00", "2012-02-16 14:42:00", "2012-02-17 >> 14:14:00", >> "2012-02-18 15:27:00", "2012-02-19 13:13:00", "2012-02-20 >> 13:56:00", >> "2012-02-21 14:39:00", "2012-02-22 15:33:00", "2012-02-23 >> 15:14:00", >> "2012-02-24 15:14:00", "2012-02-25 14:25:00", "2012-02-26 >> 14:08:00", >> "2012-02-27 14:55:00", "2012-02-28 14:40:00", "2012-02-29 >> 14:45:00", >> "2012-03-01 15:18:00", "2012-03-02 15:18:00", "2012-03-03 >> 15:43:00", >> "2012-03-04 15:16:00", "2012-03-05 15:17:00", "2012-03-06 >> 15:03:00", >> "2012-03-07 14:44:00", "2012-03-08 14:53:00", "2012-03-09 >> 15:10:00", >> "2012-03-10 14:43:00", "2012-03-11 13:37:00", "2012-03-12 >> 14:58:00", >> "2012-03-13 14:36:00", "2012-03-14 13:49:00", "2012-03-15 >> 14:32:00", >> "2012-03-16 15:01:00", "2012-03-17 13:55:00", "2012-03-18 >> 13:44:00", >> "2012-03-19 13:55:00", "2012-03-20 13:53:00", "2012-03-21 >> 14:07:00", >> "2012-03-22 14:03:00", "2012-03-23 14:30:00", "2012-03-24 >> 14:47:00", >> "2012-03-25 14:32:00", "2012-03-26 14:41:00", "2012-03-27 >> 13:51:00", >> "2012-03-28 13:32:00", "2012-03-29 13:59:00", "2012-03-30 >> 14:15:00", >> "2012-03-31 14:12:00", "2012-04-01 14:30:00", "2012-04-02 >> 13:43:00", >> "2012-04-03 13:54:00", "2012-04-04 13:45:00", "2012-04-05 >> 13:46:00", >> "2012-04-06 13:41:00", "2012-04-07 13:13:00", "2012-04-08 >> 12:59:00", >> "2012-04-09 13:53:00", "2012-04-10 14:15:00", "2012-04-11 >> 14:26:00", >> "2012-04-12 14:05:00", "2012-04-13 13:37:00", "2012-04-14 >> 13:52:00", >> "2012-04-15 15:00:00", "2012-04-16 14:42:00", "2012-04-17 >> 14:21:00", >> "2012-04-18 14:40:00", "2012-04-19 14:35:00", "2012-04-20 >> 15:14:00", >> "2012-04-21 14:46:00", "2012-04-22 14:44:00", "2012-04-23 >> 14:33:00", >> "2012-04-24 14:41:00", "2012-04-25 14:13:00", "2012-04-26 >> 14:19:00", >> "2012-04-27 14:35:00", "2012-04-28 13:48:00", "2012-04-29 >> 14:12:00", >> "2012-04-30 13:53:00", "2012-05-02 14:41:00", "2012-05-03 >> 15:01:00", >> "2012-05-04 15:21:00", "2012-05-05 14:57:00", "2012-05-06 >> 14:09:00", >> "2012-05-07 14:30:00", "2012-05-08 14:05:00", "2012-05-08 >> 21:21:00", >> "2012-05-09 15:02:00", "2012-05-10 14:27:00", "2012-05-11 >> 14:47:00", >> "2012-05-12 13:24:00", "2012-05-13 14:40:00", "2012-05-13 >> 19:24:00", >> "2012-05-14 14:33:00", "2012-05-15 14:39:00", "2012-05-16 >> 14:07:00", >> "2012-05-17 13:42:00", "2012-05-18 14:30:00", "2012-05-19 >> 13:59:00", >> "2012-05-20 14:14:00", "2012-05-21 14:15:00", "2012-05-22 >> 14:18:00", >> "2012-05-23 14:14:00", "2012-05-24 13:52:00"), class = >> "factor"), >> fcst = c(38.7, 38.9, 39.2, 39.8, 40.5, 41.5, 42.5, 43.1, >> 43.9, 44.5, 44.8, 45, 45, 45.1, 45.4, 45.8, 46.4, 47, 47.5, >> 47.9, 39.2, 40, 41.8, 42.2, 42.8, 44.4, 45.7, 46.2, 46.2, >> 46.2, 46.5, 47, 47.5, 47.9, 48.4, 49, 49.5, 49.9, 50.2, >> 50.4, >> 41.3, 42.5, 42.8, 42.8, 42.8, 42.9, 43, 43.3, 43.5, 43.8), >> usgs = c(38.5, 38.6, 38.6, 38.6, 39.1, 39.8, 41.2, 42.9, >> 43.4, 43.6, 43.4, 43.1, 43, 43.1, 43.5, 43.8, 44.1, 44.2, >> 44.4, 44.5, 39.1, 39.8, 41.2, 42.9, 43.4, 43.6, 43.4, 43.1, >> 43, 43.1, 43.5, 43.8, 44.1, 44.2, 44.4, 44.5, 44.5, 44.5, >> 44.6, 44.2, 41.2, 42.9, 43.4, 43.6, 43.4, 43.1, 43, 43.1, >> 43.5, 43.8)), .Names = c("date", "basistime", "fcst", "usgs" >> ), row.names = c(NA, 50L), class = "data.frame") >> Sys.setenv( "Etc/GMT+8" ) # or whatever is appropriate >> #> Error in Sys.setenv("Etc/GMT+8"): all arguments must be named >> dta2 <- dta >> # bad idea to work with dates as factors >> dta2$date <- as.POSIXct( as.character( dta2$date ) ) >> dta2$basistime <- as.POSIXct( as.character( dta2$basistime ) ) >> # base R solution >> dates <- unique( dta2$date ) >> dta2list <- split( dta2, dta2$date ) >> grplist <- lapply( dta2list >> , function( DF ) { >> DF[ which.max( DF$fcst ), ] >> } >> ) >> result2 <- do.call( rbind, grplist ) >> result2 >> #> date basistime fcst >> usgs >> #> 2012-01-25 18:00:00 2012-01-25 18:00:00 2012-01-25 15:02:00 38.7 >> 38.5 >> #> 2012-01-26 00:00:00 2012-01-26 00:00:00 2012-01-25 15:02:00 38.9 >> 38.6 >> #> 2012-01-26 06:00:00 2012-01-26 06:00:00 2012-01-25 15:02:00 39.2 >> 38.6 >> #> 2012-01-26 12:00:00 2012-01-26 12:00:00 2012-01-25 15:02:00 39.8 >> 38.6 >> #> 2012-01-26 18:00:00 2012-01-26 18:00:00 2012-01-25 15:02:00 40.5 >> 39.1 >> #> 2012-01-27 00:00:00 2012-01-27 00:00:00 2012-01-25 15:02:00 41.5 >> 39.8 >> #> 2012-01-27 06:00:00 2012-01-27 06:00:00 2012-01-25 15:02:00 42.5 >> 41.2 >> #> 2012-01-27 12:00:00 2012-01-27 12:00:00 2012-01-25 15:02:00 43.1 >> 42.9 >> #> 2012-01-27 18:00:00 2012-01-27 18:00:00 2012-01-25 15:02:00 43.9 >> 43.4 >> #> 2012-01-28 00:00:00 2012-01-28 00:00:00 2012-01-25 15:02:00 44.5 >> 43.6 >> #> 2012-01-28 06:00:00 2012-01-28 06:00:00 2012-01-26 15:11:00 45.7 >> 43.4 >> #> 2012-01-28 12:00:00 2012-01-28 12:00:00 2012-01-26 15:11:00 46.2 >> 43.1 >> #> 2012-01-28 18:00:00 2012-01-28 18:00:00 2012-01-26 15:11:00 46.2 >> 43.0 >> #> 2012-01-29 00:00:00 2012-01-29 00:00:00 2012-01-26 15:11:00 46.2 >> 43.1 >> #> 2012-01-29 06:00:00 2012-01-29 06:00:00 2012-01-26 15:11:00 46.5 >> 43.5 >> #> 2012-01-29 12:00:00 2012-01-29 12:00:00 2012-01-26 15:11:00 47.0 >> 43.8 >> #> 2012-01-29 18:00:00 2012-01-29 18:00:00 2012-01-26 15:11:00 47.5 >> 44.1 >> #> 2012-01-30 00:00:00 2012-01-30 00:00:00 2012-01-26 15:11:00 47.9 >> 44.2 >> #> 2012-01-30 06:00:00 2012-01-30 06:00:00 2012-01-26 15:11:00 48.4 >> 44.4 >> #> 2012-01-30 12:00:00 2012-01-30 12:00:00 2012-01-26 15:11:00 49.0 >> 44.5 >> #> 2012-01-30 18:00:00 2012-01-30 18:00:00 2012-01-26 15:11:00 49.5 >> 44.5 >> #> 2012-01-31 00:00:00 2012-01-31 00:00:00 2012-01-26 15:11:00 49.9 >> 44.5 >> #> 2012-01-31 06:00:00 2012-01-31 06:00:00 2012-01-26 15:11:00 50.2 >> 44.6 >> #> 2012-01-31 12:00:00 2012-01-31 12:00:00 2012-01-26 15:11:00 50.4 >> 44.2 >> # alternately, use tidyverse >> library(dplyr) >> #> >> #> Attaching package: 'dplyr' >> #> The following objects are masked from 'package:stats': >> #> >> #> filter, lag >> #> The following objects are masked from 'package:base': >> #> >> #> intersect, setdiff, setequal, union >> result3 <- ( dta2 >> %>% group_by( date ) >> %>% do({ >> DF <- . >> DF[ which.max( DF$fcst ), ] >> }) >> %>% ungroup >> %>% as.data.frame >> ) >> result3 >> #> date basistime fcst usgs >> #> 1 2012-01-25 18:00:00 2012-01-25 15:02:00 38.7 38.5 >> #> 2 2012-01-26 00:00:00 2012-01-25 15:02:00 38.9 38.6 >> #> 3 2012-01-26 06:00:00 2012-01-25 15:02:00 39.2 38.6 >> #> 4 2012-01-26 12:00:00 2012-01-25 15:02:00 39.8 38.6 >> #> 5 2012-01-26 18:00:00 2012-01-25 15:02:00 40.5 39.1 >> #> 6 2012-01-27 00:00:00 2012-01-25 15:02:00 41.5 39.8 >> #> 7 2012-01-27 06:00:00 2012-01-25 15:02:00 42.5 41.2 >> #> 8 2012-01-27 12:00:00 2012-01-25 15:02:00 43.1 42.9 >> #> 9 2012-01-27 18:00:00 2012-01-25 15:02:00 43.9 43.4 >> #> 10 2012-01-28 00:00:00 2012-01-25 15:02:00 44.5 43.6 >> #> 11 2012-01-28 06:00:00 2012-01-26 15:11:00 45.7 43.4 >> #> 12 2012-01-28 12:00:00 2012-01-26 15:11:00 46.2 43.1 >> #> 13 2012-01-28 18:00:00 2012-01-26 15:11:00 46.2 43.0 >> #> 14 2012-01-29 00:00:00 2012-01-26 15:11:00 46.2 43.1 >> #> 15 2012-01-29 06:00:00 2012-01-26 15:11:00 46.5 43.5 >> #> 16 2012-01-29 12:00:00 2012-01-26 15:11:00 47.0 43.8 >> #> 17 2012-01-29 18:00:00 2012-01-26 15:11:00 47.5 44.1 >> #> 18 2012-01-30 00:00:00 2012-01-26 15:11:00 47.9 44.2 >> #> 19 2012-01-30 06:00:00 2012-01-26 15:11:00 48.4 44.4 >> #> 20 2012-01-30 12:00:00 2012-01-26 15:11:00 49.0 44.5 >> #> 21 2012-01-30 18:00:00 2012-01-26 15:11:00 49.5 44.5 >> #> 22 2012-01-31 00:00:00 2012-01-26 15:11:00 49.9 44.5 >> #> 23 2012-01-31 06:00:00 2012-01-26 15:11:00 50.2 44.6 >> #> 24 2012-01-31 12:00:00 2012-01-26 15:11:00 50.4 44.2 >> #################################################### >> On Thu, 26 Oct 2017, Thomas Adams wrote: >> >> Hello all! >> >> I've been struggling with is for many hours today; I'm >> close to getting >> what I want, but not close enough... >> >> I have a dataframe consisting of two date-time columns >> followed by two >> numeric columns. what I need is the max value (in the >> first numeric column) >> based on the 2nd date-time column, which is essentially a >> factor. But, I >> want the result to provide both date-time values >> corresponding to the max >> value. >> >> My data: >> >> structure(list(date = structure(c(1L, 2L, 3L, 4L, 5L, 6L, >> 7L, >> 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, >> 20L, >> 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, >> 17L, 18L, >> 19L, 20L, 21L, 22L, 23L, 24L, 7L, 8L, 9L, 10L, 11L, 12L, >> 13L, >> 14L, 15L, 16L), .Label = c("2012-01-25 18:00:00", >> "2012-01-26 00:00:00", >> "2012-01-26 06:00:00", "2012-01-26 12:00:00", "2012-01-26 >> 18:00:00", >> "2012-01-27 00:00:00", "2012-01-27 06:00:00", "2012-01-27 >> 12:00:00", >> "2012-01-27 18:00:00", "2012-01-28 00:00:00", "2012-01-28 >> 06:00:00", >> "2012-01-28 12:00:00", "2012-01-28 18:00:00", "2012-01-29 >> 00:00:00", >> "2012-01-29 06:00:00", "2012-01-29 12:00:00", "2012-01-29 >> 18:00:00", >> "2012-01-30 00:00:00", "2012-01-30 06:00:00", "2012-01-30 >> 12:00:00", >> "2012-01-30 18:00:00", "2012-01-31 00:00:00", "2012-01-31 >> 06:00:00", >> "2012-01-31 12:00:00", "2012-01-31 13:00:00", "2012-01-31 >> 18:00:00", >> "2012-02-01 00:00:00", "2012-02-01 06:00:00", "2012-02-01 >> 12:00:00", >> "2012-02-01 18:00:00", "2012-02-02 00:00:00", "2012-02-02 >> 06:00:00", >> "2012-02-02 12:00:00", "2012-02-02 18:00:00", "2012-02-03 >> 00:00:00", >> "2012-02-03 06:00:00", "2012-02-03 12:00:00", "2012-02-03 >> 18:00:00", >> "2012-02-04 00:00:00", "2012-02-04 06:00:00", "2012-02-04 >> 12:00:00", >> "2012-02-04 18:00:00", "2012-02-05 00:00:00", "2012-02-05 >> 06:00:00", >> "2012-02-05 12:00:00", "2012-02-05 18:00:00", "2012-02-06 >> 00:00:00", >> "2012-02-06 06:00:00", "2012-02-06 12:00:00", "2012-02-06 >> 18:00:00", >> "2012-02-07 00:00:00", "2012-02-07 06:00:00", "2012-02-07 >> 12:00:00", >> "2012-02-07 18:00:00", "2012-02-08 00:00:00", "2012-02-08 >> 06:00:00", >> "2012-02-08 12:00:00", "2012-02-08 18:00:00", "2012-02-09 >> 00:00:00", >> "2012-02-09 06:00:00", "2012-02-09 12:00:00", "2012-02-09 >> 18:00:00", >> "2012-02-10 00:00:00", "2012-02-10 06:00:00", "2012-02-10 >> 12:00:00", >> "2012-02-10 18:00:00", "2012-02-11 00:00:00", "2012-02-11 >> 06:00:00", >> "2012-02-11 12:00:00", "2012-02-11 18:00:00", "2012-02-12 >> 00:00:00", >> "2012-02-12 06:00:00", "2012-02-12 12:00:00", "2012-02-12 >> 18:00:00", >> "2012-02-13 00:00:00", "2012-02-13 06:00:00", "2012-02-13 >> 12:00:00", >> "2012-02-13 18:00:00", "2012-02-14 00:00:00", "2012-02-14 >> 06:00:00", >> "2012-02-14 12:00:00", "2012-02-14 18:00:00", "2012-02-15 >> 00:00:00", >> "2012-02-15 06:00:00", "2012-02-15 12:00:00", "2012-02-15 >> 18:00:00", >> "2012-02-16 00:00:00", "2012-02-16 06:00:00", "2012-02-16 >> 12:00:00", >> "2012-02-16 18:00:00", "2012-02-17 00:00:00", "2012-02-17 >> 06:00:00", >> "2012-02-17 12:00:00", "2012-02-17 18:00:00", "2012-02-18 >> 00:00:00", >> "2012-02-18 06:00:00", "2012-02-18 12:00:00", "2012-02-18 >> 18:00:00", >> "2012-02-19 00:00:00", "2012-02-19 06:00:00", "2012-02-19 >> 12:00:00", >> "2012-02-19 18:00:00", "2012-02-20 00:00:00", "2012-02-20 >> 06:00:00", >> "2012-02-20 12:00:00", "2012-02-20 18:00:00", "2012-02-21 >> 00:00:00", >> "2012-02-21 06:00:00", "2012-02-21 12:00:00", "2012-02-21 >> 18:00:00", >> "2012-02-22 00:00:00", "2012-02-22 06:00:00", "2012-02-22 >> 12:00:00", >> "2012-02-22 18:00:00", "2012-02-23 00:00:00", "2012-02-23 >> 06:00:00", >> "2012-02-23 12:00:00", "2012-02-23 18:00:00", "2012-02-24 >> 00:00:00", >> "2012-02-24 06:00:00", "2012-02-24 12:00:00", "2012-02-24 >> 18:00:00", >> "2012-02-25 00:00:00", "2012-02-25 06:00:00", "2012-02-25 >> 12:00:00", >> "2012-02-25 18:00:00", "2012-02-26 00:00:00", "2012-02-26 >> 06:00:00", >> "2012-02-26 12:00:00", "2012-02-26 18:00:00", "2012-02-27 >> 00:00:00", >> "2012-02-27 06:00:00", "2012-02-27 12:00:00", "2012-02-27 >> 18:00:00", >> "2012-02-28 00:00:00", "2012-02-28 06:00:00", "2012-02-28 >> 12:00:00", >> "2012-02-28 18:00:00", "2012-02-29 00:00:00", "2012-02-29 >> 06:00:00", >> "2012-02-29 12:00:00", "2012-02-29 18:00:00", "2012-03-01 >> 00:00:00", >> "2012-03-01 06:00:00", "2012-03-01 12:00:00", "2012-03-01 >> 18:00:00", >> "2012-03-02 00:00:00", "2012-03-02 06:00:00", "2012-03-02 >> 12:00:00", >> "2012-03-02 18:00:00", "2012-03-03 00:00:00", "2012-03-03 >> 06:00:00", >> "2012-03-03 12:00:00", "2012-03-03 18:00:00", "2012-03-04 >> 00:00:00", >> "2012-03-04 06:00:00", "2012-03-04 12:00:00", "2012-03-04 >> 18:00:00", >> "2012-03-05 00:00:00", "2012-03-05 06:00:00", "2012-03-05 >> 12:00:00", >> "2012-03-05 18:00:00", "2012-03-06 00:00:00", "2012-03-06 >> 06:00:00", >> "2012-03-06 12:00:00", "2012-03-06 18:00:00", "2012-03-07 >> 00:00:00", >> "2012-03-07 06:00:00", "2012-03-07 12:00:00", "2012-03-07 >> 18:00:00", >> "2012-03-08 00:00:00", "2012-03-08 06:00:00", "2012-03-08 >> 12:00:00", >> "2012-03-08 18:00:00", "2012-03-09 00:00:00", "2012-03-09 >> 06:00:00", >> "2012-03-09 12:00:00", "2012-03-09 18:00:00", "2012-03-10 >> 00:00:00", >> "2012-03-10 06:00:00", "2012-03-10 12:00:00", "2012-03-10 >> 18:00:00", >> "2012-03-11 00:00:00", "2012-03-11 06:00:00", "2012-03-11 >> 12:00:00", >> "2012-03-11 18:00:00", "2012-03-12 00:00:00", "2012-03-12 >> 06:00:00", >> "2012-03-12 12:00:00", "2012-03-12 18:00:00", "2012-03-13 >> 00:00:00", >> "2012-03-13 06:00:00", "2012-03-13 12:00:00", "2012-03-13 >> 18:00:00", >> "2012-03-14 00:00:00", "2012-03-14 06:00:00", "2012-03-14 >> 12:00:00", >> "2012-03-14 18:00:00", "2012-03-15 00:00:00", "2012-03-15 >> 06:00:00", >> "2012-03-15 12:00:00", "2012-03-15 18:00:00", "2012-03-16 >> 00:00:00", >> "2012-03-16 06:00:00", "2012-03-16 12:00:00", "2012-03-16 >> 18:00:00", >> "2012-03-17 00:00:00", "2012-03-17 06:00:00", "2012-03-17 >> 12:00:00", >> "2012-03-17 18:00:00", "2012-03-18 00:00:00", "2012-03-18 >> 06:00:00", >> "2012-03-18 12:00:00", "2012-03-18 18:00:00", "2012-03-19 >> 00:00:00", >> "2012-03-19 06:00:00", "2012-03-19 12:00:00", "2012-03-19 >> 18:00:00", >> "2012-03-20 00:00:00", "2012-03-20 06:00:00", "2012-03-20 >> 12:00:00", >> "2012-03-20 18:00:00", "2012-03-21 00:00:00", "2012-03-21 >> 06:00:00", >> "2012-03-21 12:00:00", "2012-03-21 18:00:00", "2012-03-22 >> 00:00:00", >> "2012-03-22 06:00:00", "2012-03-22 12:00:00", "2012-03-22 >> 18:00:00", >> "2012-03-23 00:00:00", "2012-03-23 06:00:00", "2012-03-23 >> 12:00:00", >> "2012-03-23 18:00:00", "2012-03-24 00:00:00", "2012-03-24 >> 06:00:00", >> "2012-03-24 12:00:00", "2012-03-24 18:00:00", "2012-03-25 >> 00:00:00", >> "2012-03-25 06:00:00", "2012-03-25 12:00:00", "2012-03-25 >> 18:00:00", >> "2012-03-26 00:00:00", "2012-03-26 06:00:00", "2012-03-26 >> 12:00:00", >> "2012-03-26 18:00:00", "2012-03-27 00:00:00", "2012-03-27 >> 06:00:00", >> "2012-03-27 12:00:00", "2012-03-27 18:00:00", "2012-03-28 >> 00:00:00", >> "2012-03-28 06:00:00", "2012-03-28 12:00:00", "2012-03-28 >> 18:00:00", >> "2012-03-29 00:00:00", "2012-03-29 06:00:00", "2012-03-29 >> 12:00:00", >> "2012-03-29 18:00:00", "2012-03-30 00:00:00", "2012-03-30 >> 06:00:00", >> "2012-03-30 12:00:00", "2012-03-30 18:00:00", "2012-03-31 >> 00:00:00", >> "2012-03-31 06:00:00", "2012-03-31 12:00:00", "2012-03-31 >> 18:00:00", >> "2012-04-01 00:00:00", "2012-04-01 06:00:00", "2012-04-01 >> 12:00:00", >> "2012-04-01 18:00:00", "2012-04-02 00:00:00", "2012-04-02 >> 06:00:00", >> "2012-04-02 12:00:00", "2012-04-02 18:00:00", "2012-04-03 >> 00:00:00", >> "2012-04-03 06:00:00", "2012-04-03 12:00:00", "2012-04-03 >> 18:00:00", >> "2012-04-04 00:00:00", "2012-04-04 06:00:00", "2012-04-04 >> 12:00:00", >> "2012-04-04 18:00:00", "2012-04-05 00:00:00", "2012-04-05 >> 06:00:00", >> "2012-04-05 12:00:00", "2012-04-05 18:00:00", "2012-04-06 >> 00:00:00", >> "2012-04-06 06:00:00", "2012-04-06 12:00:00", "2012-04-06 >> 18:00:00", >> "2012-04-07 00:00:00", "2012-04-07 06:00:00", "2012-04-07 >> 12:00:00", >> "2012-04-07 18:00:00", "2012-04-08 00:00:00", "2012-04-08 >> 06:00:00", >> "2012-04-08 12:00:00", "2012-04-08 18:00:00", "2012-04-09 >> 00:00:00", >> "2012-04-09 06:00:00", "2012-04-09 12:00:00", "2012-04-09 >> 18:00:00", >> "2012-04-10 00:00:00", "2012-04-10 06:00:00", "2012-04-10 >> 12:00:00", >> "2012-04-10 18:00:00", "2012-04-11 00:00:00", "2012-04-11 >> 06:00:00", >> "2012-04-11 12:00:00", "2012-04-11 18:00:00", "2012-04-12 >> 00:00:00", >> "2012-04-12 06:00:00", "2012-04-12 12:00:00", "2012-04-12 >> 18:00:00", >> "2012-04-13 00:00:00", "2012-04-13 06:00:00", "2012-04-13 >> 12:00:00", >> "2012-04-13 18:00:00", "2012-04-14 00:00:00", "2012-04-14 >> 06:00:00", >> "2012-04-14 12:00:00", "2012-04-14 18:00:00", "2012-04-15 >> 00:00:00", >> "2012-04-15 06:00:00", "2012-04-15 12:00:00", "2012-04-15 >> 18:00:00", >> "2012-04-16 00:00:00", "2012-04-16 06:00:00", "2012-04-16 >> 12:00:00", >> "2012-04-16 18:00:00", "2012-04-17 00:00:00", "2012-04-17 >> 06:00:00", >> "2012-04-17 12:00:00", "2012-04-17 18:00:00", "2012-04-18 >> 00:00:00", >> "2012-04-18 06:00:00", "2012-04-18 12:00:00", "2012-04-18 >> 18:00:00", >> "2012-04-19 00:00:00", "2012-04-19 06:00:00", "2012-04-19 >> 12:00:00", >> "2012-04-19 18:00:00", "2012-04-20 00:00:00", "2012-04-20 >> 06:00:00", >> "2012-04-20 12:00:00", "2012-04-20 18:00:00", "2012-04-21 >> 00:00:00", >> "2012-04-21 06:00:00", "2012-04-21 12:00:00", "2012-04-21 >> 18:00:00", >> "2012-04-22 00:00:00", "2012-04-22 06:00:00", "2012-04-22 >> 12:00:00", >> "2012-04-22 18:00:00", "2012-04-23 00:00:00", "2012-04-23 >> 06:00:00", >> "2012-04-23 12:00:00", "2012-04-23 18:00:00", "2012-04-24 >> 00:00:00", >> "2012-04-24 06:00:00", "2012-04-24 12:00:00", "2012-04-24 >> 18:00:00", >> "2012-04-25 00:00:00", "2012-04-25 06:00:00", "2012-04-25 >> 12:00:00", >> "2012-04-25 18:00:00", "2012-04-26 00:00:00", "2012-04-26 >> 06:00:00", >> "2012-04-26 12:00:00", "2012-04-26 18:00:00", "2012-04-27 >> 00:00:00", >> "2012-04-27 06:00:00", "2012-04-27 12:00:00", "2012-04-27 >> 18:00:00", >> "2012-04-28 00:00:00", "2012-04-28 06:00:00", "2012-04-28 >> 12:00:00", >> "2012-04-28 18:00:00", "2012-04-29 00:00:00", "2012-04-29 >> 06:00:00", >> "2012-04-29 12:00:00", "2012-04-29 18:00:00", "2012-04-30 >> 00:00:00", >> "2012-04-30 06:00:00", "2012-04-30 12:00:00", "2012-04-30 >> 18:00:00", >> "2012-05-01 00:00:00", "2012-05-01 06:00:00", "2012-05-01 >> 12:00:00", >> "2012-05-01 18:00:00", "2012-05-02 00:00:00", "2012-05-02 >> 06:00:00", >> "2012-05-02 12:00:00", "2012-05-02 18:00:00", "2012-05-03 >> 00:00:00", >> "2012-05-03 06:00:00", "2012-05-03 12:00:00", "2012-05-03 >> 18:00:00", >> "2012-05-04 00:00:00", "2012-05-04 06:00:00", "2012-05-04 >> 12:00:00", >> "2012-05-04 18:00:00", "2012-05-05 00:00:00", "2012-05-05 >> 06:00:00", >> "2012-05-05 12:00:00", "2012-05-05 18:00:00", "2012-05-06 >> 00:00:00", >> "2012-05-06 06:00:00", "2012-05-06 12:00:00", "2012-05-06 >> 18:00:00", >> "2012-05-07 00:00:00", "2012-05-07 06:00:00", "2012-05-07 >> 12:00:00", >> "2012-05-07 18:00:00", "2012-05-08 00:00:00", "2012-05-08 >> 06:00:00", >> "2012-05-08 12:00:00", "2012-05-08 18:00:00", "2012-05-09 >> 00:00:00", >> "2012-05-09 06:00:00", "2012-05-09 12:00:00", "2012-05-09 >> 18:00:00", >> "2012-05-10 00:00:00", "2012-05-10 06:00:00", "2012-05-10 >> 12:00:00", >> "2012-05-10 18:00:00", "2012-05-11 00:00:00", "2012-05-11 >> 06:00:00", >> "2012-05-11 12:00:00", "2012-05-11 18:00:00", "2012-05-12 >> 00:00:00", >> "2012-05-12 06:00:00", "2012-05-12 12:00:00", "2012-05-12 >> 18:00:00", >> "2012-05-13 00:00:00", "2012-05-13 06:00:00", "2012-05-13 >> 12:00:00", >> "2012-05-13 18:00:00", "2012-05-14 00:00:00", "2012-05-14 >> 06:00:00", >> "2012-05-14 12:00:00", "2012-05-14 18:00:00", "2012-05-15 >> 00:00:00", >> "2012-05-15 06:00:00", "2012-05-15 12:00:00", "2012-05-15 >> 18:00:00", >> "2012-05-16 00:00:00", "2012-05-16 06:00:00", "2012-05-16 >> 12:00:00", >> "2012-05-16 18:00:00", "2012-05-17 00:00:00", "2012-05-17 >> 06:00:00", >> "2012-05-17 12:00:00", "2012-05-17 18:00:00", "2012-05-18 >> 00:00:00", >> "2012-05-18 06:00:00", "2012-05-18 12:00:00", "2012-05-18 >> 18:00:00", >> "2012-05-19 00:00:00", "2012-05-19 06:00:00", "2012-05-19 >> 12:00:00", >> "2012-05-19 18:00:00", "2012-05-20 00:00:00", "2012-05-20 >> 06:00:00", >> "2012-05-20 12:00:00", "2012-05-20 18:00:00", "2012-05-21 >> 00:00:00", >> "2012-05-21 06:00:00", "2012-05-21 12:00:00", "2012-05-21 >> 18:00:00", >> "2012-05-22 00:00:00", "2012-05-22 06:00:00", "2012-05-22 >> 12:00:00", >> "2012-05-22 18:00:00", "2012-05-23 00:00:00", "2012-05-23 >> 06:00:00", >> "2012-05-23 12:00:00", "2012-05-23 18:00:00", "2012-05-24 >> 00:00:00", >> "2012-05-24 06:00:00", "2012-05-24 12:00:00", "2012-05-24 >> 18:00:00", >> "2012-05-25 00:00:00", "2012-05-25 06:00:00", "2012-05-25 >> 12:00:00", >> "2012-05-25 18:00:00", "2012-05-26 00:00:00", "2012-05-26 >> 06:00:00", >> "2012-05-26 12:00:00", "2012-05-26 18:00:00", "2012-05-27 >> 00:00:00", >> "2012-05-27 06:00:00", "2012-05-27 12:00:00", "2012-05-27 >> 18:00:00", >> "2012-05-28 00:00:00", "2012-05-28 06:00:00", "2012-05-28 >> 12:00:00", >> "2012-05-28 18:00:00", "2012-05-29 00:00:00", "2012-05-29 >> 06:00:00", >> "2012-05-29 12:00:00"), class = "factor"), basistime = >> structure(c(1L, >> 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, >> 1L, 1L, >> 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, >> 2L, 2L, >> 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, >> 3L, 3L, >> 3L), .Label = c("2012-01-25 15:02:00", "2012-01-26 >> 15:11:00", >> "2012-01-27 01:41:00", "2012-01-27 10:15:00", "2012-01-27 >> 15:15:00", >> "2012-01-28 14:22:00", "2012-01-29 13:33:00", "2012-01-30 >> 14:11:00", >> "2012-01-31 14:24:00", "2012-02-01 14:55:00", "2012-02-02 >> 14:56:00", >> "2012-02-03 14:40:00", "2012-02-04 15:01:00", "2012-02-05 >> 15:04:00", >> "2012-02-06 14:37:00", "2012-02-07 14:42:00", "2012-02-08 >> 14:44:00", >> "2012-02-09 14:27:00", "2012-02-10 14:33:00", "2012-02-11 >> 15:05:00", >> "2012-02-12 15:09:00", "2012-02-13 15:00:00", "2012-02-14 >> 15:10:00", >> "2012-02-15 14:46:00", "2012-02-16 14:42:00", "2012-02-17 >> 14:14:00", >> "2012-02-18 15:27:00", "2012-02-19 13:13:00", "2012-02-20 >> 13:56:00", >> "2012-02-21 14:39:00", "2012-02-22 15:33:00", "2012-02-23 >> 15:14:00", >> "2012-02-24 15:14:00", "2012-02-25 14:25:00", "2012-02-26 >> 14:08:00", >> "2012-02-27 14:55:00", "2012-02-28 14:40:00", "2012-02-29 >> 14:45:00", >> "2012-03-01 15:18:00", "2012-03-02 15:18:00", "2012-03-03 >> 15:43:00", >> "2012-03-04 15:16:00", "2012-03-05 15:17:00", "2012-03-06 >> 15:03:00", >> "2012-03-07 14:44:00", "2012-03-08 14:53:00", "2012-03-09 >> 15:10:00", >> "2012-03-10 14:43:00", "2012-03-11 13:37:00", "2012-03-12 >> 14:58:00", >> "2012-03-13 14:36:00", "2012-03-14 13:49:00", "2012-03-15 >> 14:32:00", >> "2012-03-16 15:01:00", "2012-03-17 13:55:00", "2012-03-18 >> 13:44:00", >> "2012-03-19 13:55:00", "2012-03-20 13:53:00", "2012-03-21 >> 14:07:00", >> "2012-03-22 14:03:00", "2012-03-23 14:30:00", "2012-03-24 >> 14:47:00", >> "2012-03-25 14:32:00", "2012-03-26 14:41:00", "2012-03-27 >> 13:51:00", >> "2012-03-28 13:32:00", "2012-03-29 13:59:00", "2012-03-30 >> 14:15:00", >> "2012-03-31 14:12:00", "2012-04-01 14:30:00", "2012-04-02 >> 13:43:00", >> "2012-04-03 13:54:00", "2012-04-04 13:45:00", "2012-04-05 >> 13:46:00", >> "2012-04-06 13:41:00", "2012-04-07 13:13:00", "2012-04-08 >> 12:59:00", >> "2012-04-09 13:53:00", "2012-04-10 14:15:00", "2012-04-11 >> 14:26:00", >> "2012-04-12 14:05:00", "2012-04-13 13:37:00", "2012-04-14 >> 13:52:00", >> "2012-04-15 15:00:00", "2012-04-16 14:42:00", "2012-04-17 >> 14:21:00", >> "2012-04-18 14:40:00", "2012-04-19 14:35:00", "2012-04-20 >> 15:14:00", >> "2012-04-21 14:46:00", "2012-04-22 14:44:00", "2012-04-23 >> 14:33:00", >> "2012-04-24 14:41:00", "2012-04-25 14:13:00", "2012-04-26 >> 14:19:00", >> "2012-04-27 14:35:00", "2012-04-28 13:48:00", "2012-04-29 >> 14:12:00", >> "2012-04-30 13:53:00", "2012-05-02 14:41:00", "2012-05-03 >> 15:01:00", >> "2012-05-04 15:21:00", "2012-05-05 14:57:00", "2012-05-06 >> 14:09:00", >> "2012-05-07 14:30:00", "2012-05-08 14:05:00", "2012-05-08 >> 21:21:00", >> "2012-05-09 15:02:00", "2012-05-10 14:27:00", "2012-05-11 >> 14:47:00", >> "2012-05-12 13:24:00", "2012-05-13 14:40:00", "2012-05-13 >> 19:24:00", >> "2012-05-14 14:33:00", "2012-05-15 14:39:00", "2012-05-16 >> 14:07:00", >> "2012-05-17 13:42:00", "2012-05-18 14:30:00", "2012-05-19 >> 13:59:00", >> "2012-05-20 14:14:00", "2012-05-21 14:15:00", "2012-05-22 >> 14:18:00", >> "2012-05-23 14:14:00", "2012-05-24 13:52:00"), class = >> "factor"), >> fcst = c(38.7, 38.9, 39.2, 39.8, 40.5, 41.5, 42.5, >> 43.1, >> 43.9, 44.5, 44.8, 45, 45, 45.1, 45.4, 45.8, 46.4, 47, >> 47.5, >> 47.9, 39.2, 40, 41.8, 42.2, 42.8, 44.4, 45.7, 46.2, >> 46.2, >> 46.2, 46.5, 47, 47.5, 47.9, 48.4, 49, 49.5, 49.9, 50.2, >> 50.4, >> 41.3, 42.5, 42.8, 42.8, 42.8, 42.9, 43, 43.3, 43.5, >> 43.8), >> usgs = c(38.5, 38.6, 38.6, 38.6, 39.1, 39.8, 41.2, >> 42.9, >> 43.4, 43.6, 43.4, 43.1, 43, 43.1, 43.5, 43.8, 44.1, >> 44.2, >> 44.4, 44.5, 39.1, 39.8, 41.2, 42.9, 43.4, 43.6, 43.4, >> 43.1, >> 43, 43.1, 43.5, 43.8, 44.1, 44.2, 44.4, 44.5, 44.5, >> 44.5, >> 44.6, 44.2, 41.2, 42.9, 43.4, 43.6, 43.4, 43.1, 43, >> 43.1, >> 43.5, 43.8)), .Names = c("date", "basistime", "fcst", >> "usgs" >> ), row.names = c(NA, 50L), class = "data.frame") >> >> aggregate(fcst ~ basistime,data=legacy, FUN= max) >> >> A snippet... >> >> basistime fcst >> 1 2012-01-25 15:02:00 47.9 >> 2 2012-01-26 15:11:00 50.4 >> 3 2012-01-27 01:41:00 46.0 >> 4 2012-01-27 10:15:00 47.3 >> 5 2012-01-27 15:15:00 47.3 >> 6 2012-01-28 14:22:00 46.2 >> 7 2012-01-29 13:33:00 45.8 >> 8 2012-01-30 14:11:00 44.8 >> 9 2012-01-31 14:24:00 43.9 >> 10 2012-02-01 14:55:00 41.1 >> 11 2012-02-02 14:56:00 38.1 >> 12 2012-02-03 14:40:00 36.2 >> 13 2012-02-04 15:01:00 34.7 >> 14 2012-02-05 15:04:00 33.1 >> 15 2012-02-06 14:37:00 32.2 >> >> This is what I want, except I need the other corresponding >> date-time column >> as well. I've tried this with the date-times as factors >> and as POSIXct >> values and using many of the combinations suggested in the >> documentation >> and other examples. The closest I can get returns the >> second date as a >> numeric value: >> >> aggregate(cbind(fcst,date) ~ basistime,data=legacy, FUN= >> max) >> >> Produces: >> >> basistime fcst date >> 1 2012-01-25 15:02:00 47.9 1327942800 >> 2 2012-01-26 15:11:00 50.4 1328029200 >> 3 2012-01-27 01:41:00 46.0 1328072400 >> 4 2012-01-27 10:15:00 47.3 1328032800 >> 5 2012-01-27 15:15:00 47.3 1328115600 >> 6 2012-01-28 14:22:00 46.2 1328202000 >> 7 2012-01-29 13:33:00 45.8 1328288400 >> 8 2012-01-30 14:11:00 44.8 1328374800 >> 9 2012-01-31 14:24:00 43.9 1328461200 >> 10 2012-02-01 14:55:00 41.1 1328547600 >> 11 2012-02-02 14:56:00 38.1 1328634000 >> 12 2012-02-03 14:40:00 36.2 1328720400 >> 13 2012-02-04 15:01:00 34.7 1328806800 >> 14 2012-02-05 15:04:00 33.1 1328893200 >> 15 2012-02-06 14:37:00 32.2 1328979600 >> 16 2012-02-07 14:42:00 31.2 1329066000 >> 17 2012-02-08 14:44:00 30.4 1329152400 >> 18 2012-02-09 14:27:00 30.0 1329238800 >> >> Help is greatly appreciated! >> >> Regards, >> Tom >> >> -- >> [[alternative HTML version deleted]] >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, >> see >> 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. >> --------------------------------------------------------------------------- >> Jeff Newmiller The ..... ..... Go >> Live... >> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live >> Go... >> Live: OO#.. Dead: OO#.. >> Playing >> Research Engineer (Solar/Batteries O.O#. #.O#. with >> /Software/Embedded Controllers) .OO#. .OO#. >> rocks...1k >> --------------------------------------------------------------------------- >> -- >> Thomas E Adams, III1724 Sage Lane >> Blacksburg, VA 24060 >> tea...@gmail.com (personal) >> t...@terrapredictions.org (work) >> 1 (513) 739-9512 (cell) >> > > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.