On Tue, Nov 9, 2010 at 11:23 AM, thornbird <huachang...@gmail.com> wrote: > > Thanks for your suggestion. I received a few error messages. Can anyone help > me figure out why I get the following error messages and how to solve them > by revising my code? The data is shown in the post above. Thanks. > > >> library(zoo) >> >> colClasses <- c("character", "character", "numeric", "character", >> "character", "numeric") >> >> col.names <- c("date", "day", "time", "webpage", "item", "value") >> >> # z <- read.zoo("myfile.dat", skip = 1, index = as.list(1:5), >> z <- read.zoo(testdata[,1:5],as.Date(as.character(testdata[, 1])),skip = >> 1, index = as.list(1:6), > + format = "%d/%m/%Y", col.names = col.names, > + aggregate = function(x) tail(x, 1), colClasses = colClasses) > Error in `[.data.frame`(rval, , j) : undefined columns selected >> >> >> # extract all Thursdays and Fridays >> z45 <- z[format(time(z), "%w") %in% 4:5,] > Error: object 'z' not found >> >> # keep last entry in each week >> # and show result on R console >> z45[!duplicated(format(time(z45), "%U"), fromLast = TRUE), ] > Error: object 'z45' not found
Read ?read.zoo and the three zoo vignettes (pdf documents). Assuming we wish to read in the date and value column the following first writes out a test file and then uses read.zoo to read it back in. If there are multiple records at the same date we only keep the last (see aggregate= argument). Then we perform the extraction. # create some data and write out a file with it Lines <- "date day time webpage item value 1 10-Jun-09 Wed 9:40:53 MattDamon fans 613031 2 11-Jun-09 Thu 5:27:47 MattDamon fans 630242 3 11-Jun-09 Thu 9:23:23 MattDamon fans 631966 4 11-Jun-09 Thu 22:11:33 MattDamon fans 642045 5 13-Jun-09 Sat 13:07:53 MattDamon fans 669791 6 15-Jun-09 Mon 5:07:06 MattDamon fans 700180 7 15-Jun-09 Mon 13:09:43 MattDamon fans 702949 8 16-Jun-09 Tue 22:45:27 MattDamon fans 726624 9 17-Jun-09 Wed 13:08:19 MattDamon fans 734412 10 19-Jun-09 Fri 12:37:09 MattDamon fans 765057 11 20-Jun-09 Sat 12:38:36 MattDamon fans 782741 12 21-Jun-09 Sun 12:36:25 MattDamon fans 796054 13 22-Jun-09 Mon 12:39:36 MattDamon fans 809816 14 23-Jun-09 Tue 12:40:25 MattDamon fans 833996 15 27-Jun-09 Sat 12:40:36 MattDamon fans 899900 16 28-Jun-09 Sun 12:38:07 MattDamon fans 910401 17 10-Jun-09 Wed 9:40:53 MattDamon views 613031 18 11-Jun-09 Thu 5:27:47 MattDamon views 630242 19 11-Jun-09 Thu 9:23:23 MattDamon views 631966 20 11-Jun-09 Thu 22:11:33 MattDamon views 642045 21 13-Jun-09 Sat 13:07:53 MattDamon views 669791 22 15-Jun-09 Mon 5:07:06 MattDamon views 700180 23 15-Jun-09 Mon 13:09:43 MattDamon views 702949 24 16-Jun-09 Tue 22:45:27 MattDamon views 726624 25 17-Jun-09 Wed 13:08:19 MattDamon views 734412 26 19-Jun-09 Fri 12:37:09 MattDamon views 765057 27 20-Jun-09 Sat 12:38:36 MattDamon views 782741 28 21-Jun-09 Sun 12:36:25 MattDamon views 796054 29 22-Jun-09 Mon 12:39:36 MattDamon views 809816 30 23-Jun-09 Tue 12:40:25 MattDamon views 833996 31 25-Jun-09 Thu 12:38:27 MattDamon views 871237 32 26-Jun-09 Fri 12:36:12 MattDamon views 887175 33 26-Jun-09 Fri 13:36:12 MattDamon views 887195 34 27-Jun-09 Sat 12:40:36 MattDamon views 899900 35 10-Jun-09 Wed 9:40:53 AngieeJolie fans 613031 36 11-Jun-09 Thu 5:27:47 AngieeJolie fans 630242 37 11-Jun-09 Thu 9:23:23 AngieeJolie fans 631966 38 11-Jun-09 Thu 22:11:33 AngieeJolie fans 642045 39 13-Jun-09 Sat 13:07:53 AngieeJolie fans 669791 40 15-Jun-09 Mon 5:07:06 AngieeJolie fans 700180 41 16-Jun-09 Tue 22:45:27 AngieeJolie fans 726624 42 17-Jun-09 Wed 13:08:19 AngieeJolie fans 734412 43 19-Jun-09 Fri 12:37:09 AngieeJolie fans 765057 44 20-Jun-09 Sat 12:38:36 AngieeJolie fans 782741 45 21-Jun-09 Sun 12:36:25 AngieeJolie fans 796054 46 22-Jun-09 Mon 12:39:36 AngieeJolie fans 809816 47 23-Jun-09 Tue 12:40:25 AngieeJolie fans 833996 48 25-Jun-09 Thu 12:38:27 AngieeJolie fans 871237 49 26-Jun-09 Fri 12:36:12 AngieeJolie fans 887175 50 26-Jun-09 Fri 13:36:12 AngieeJolie fans 887195 51 30-Jun-09 Tue 12:36:43 AngieeJolie fans 934280 52 10-Jun-09 Wed 9:40:53 AngieeJolie views 613031 53 11-Jun-09 Thu 5:27:47 AngieeJolie views 630242 54 11-Jun-09 Thu 9:23:23 AngieeJolie views 631966 55 11-Jun-09 Thu 22:11:33 AngieeJolie views 642045 56 13-Jun-09 Sat 13:07:53 AngieeJolie views 669791 57 15-Jun-09 Mon 5:07:06 AngieeJolie views 700180 58 15-Jun-09 Mon 13:09:43 AngieeJolie views 702949 59 16-Jun-09 Tue 22:45:27 AngieeJolie views 726624 60 17-Jun-09 Wed 13:08:19 AngieeJolie views 734412 61 19-Jun-09 Fri 12:37:09 AngieeJolie views 765057 62 20-Jun-09 Sat 12:38:36 AngieeJolie views 782741 63 21-Jun-09 Sun 12:36:25 AngieeJolie views 796054 64 22-Jun-09 Mon 12:39:36 AngieeJolie views 809816 65 23-Jun-09 Tue 12:40:25 AngieeJolie views 833996 66 25-Jun-09 Thu 12:38:27 AngieeJolie views 871237 67 26-Jun-09 Fri 12:36:12 AngieeJolie views 887175 68 26-Jun-09 Fri 13:36:12 AngieeJolie views 887195 69 27-Jun-09 Sat 12:40:36 AngieeJolie views 899900" tmp <- read.table(textConnection(Lines)) write.table(tmp, sep = ",", file = "testdata.csv", row.names = FALSE) # file.show("testdata.csv") # use read.zoo to read in "testdata.csv" library(zoo) z <- read.zoo("testdata.csv", header = TRUE, sep = ",", format = "%d-%b-%y", aggregate = function(x) tail(x, 1), colClasses = c("character", "NULL", "NULL", "NULL", "NULL", "numeric")) z[format(time(z), "%w") %in% 4:5] -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ 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.