Hello, I have some problems to sort a large data table. In particular, I would like to sort a data table in such a way that the duplicated values in two columns are disposed one below the other and if possible in an ascending order (especially for the column "Date"). An example with a short data table and associated responses are showed in http://stackoverflow.com/questions/38879961/sort-a-data-table-with-specific-value-order) . However, the proposed solutions don't work with this data table. For example, the line 24 with the value 318880 for Tag1 is not below the line 8.
[http://cdn.sstatic.net/Sites/stackoverflow/img/apple-touch-i...@2.png?v=73d79a89bded&a]<http://stackoverflow.com/questions/38879961/sort-a-data-table-with-specific-value-order> Sort a data table with specific value order<http://stackoverflow.com/questions/38879961/sort-a-data-table-with-specific-value-order> stackoverflow.com I have a data table: DT <- data.table(Tag1 = c(22,253,6219,6219,252862,252864,312786,312812), Tag2 = c(22,255,6220,252857,252863,252865,251191,252863), Date= a... DT <- data.table(Tag1 = c(252860, 252862, 312812, 252864, 252866, 252868, 252870, 318880, 252872, 252874, 252876, 252878, 252880, 252880, 252881, 252883,252885, 252887, 311264, 252889, 252889, 252892, 318879, 318880, 318881), Tag2 = c(252861, 252863, 252863, 252865, 252867, 252869, 252871, 252871, 252873,252875, 252877, 252879, 414611, 905593, 252882, 252884, 252886, 252888, 252888, 252890, 318904, 252893, 318878, 414547, 318882), Date = as.Date(as.character(c("9/6/2002","9/6/2002", "9/5/2003", "9/6/2002", "9/6/2002", "9/6/2002", "9/6/2002", "10/8/2003", "9/6/2002", "9/6/2002", "9/6/2002", "9/6/2002", "10/5/2004", "9/6/2002", "9/6/2002", "9/6/2002", "9/10/2002", "9/10/2002", "7/15/2003", "9/10/2002", "10/15/2003", "9/10/2002", "10/8/2003", "9/29/2004","10/8/2003")),format = "%m/%d/%Y")) setcolorder(dt1 <- DT[order(-Date)][order(Tag1), .SD, by = Tag2], colnames(DT)) > dt1 Tag1 Tag2 Date 1: 252860 252861 2002-09-06 2: 252862 252863 2002-09-06 3: 312812 252863 2003-09-05 4: 252864 252865 2002-09-06 5: 252866 252867 2002-09-06 6: 252868 252869 2002-09-06 7: 252870 252871 2002-09-06 8: 318880 252871 2003-10-08 9: 252872 252873 2002-09-06 10: 252874 252875 2002-09-06 11: 252876 252877 2002-09-06 12: 252878 252879 2002-09-06 13: 252880 414611 2004-10-05 14: 252880 905593 2002-09-06 15: 252881 252882 2002-09-06 16: 252883 252884 2002-09-06 17: 252885 252886 2002-09-10 18: 252887 252888 2002-09-10 19: 311264 252888 2003-07-15 20: 252889 318904 2003-10-15 21: 252889 252890 2002-09-10 22: 252892 252893 2002-09-10 23: 318879 318878 2003-10-08 24: 318880 414547 2004-09-29 25: 318881 318882 2003-10-08 Thanks a lot for your time. Have a nice day Nell [[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.
