Rex: sample(n)
is a much better way to get random permutations of 1:n. To be clear, this is sample(n,replace = FALSE) , the default. (I have no idea whether this is what the poster needs. I just wanted to correct the clumsy order(runif) construction). -- Bert On Wed, Mar 9, 2011 at 10:28 AM, <rex.dw...@syngenta.com> wrote: > It sounds like you want a bunch of random permutations of 1:7. > Try order(runif(7)) > If you need, say, 10 of them: > as.vector(sapply(1:10,function(i) order(runif(7)))) > Is it more complicated than that? > > > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Hosack, Michael > Sent: Wednesday, March 09, 2011 1:02 PM > To: r-help@R-project.org > Subject: [R] Complex sampling? > >> -----Original Message----- >> From: r-help-bounces at r-project.org [mailto:r-help-bounces at >> r-project.org] >> On Behalf Of Hosack, Michael >> Sent: Wednesday, March 09, 2011 7:34 AM >> To: r-help at R-project.org >> Subject: [R] Complex sampling? >> >> R users, >> >> I am trying to generate a randomized weekday survey schedule that ensures >> even coverage of weekdays in >> the sample, where the distribution of variable DOW is random with respect >> to WEEK. To accomplish this I need >> to randomly sample without replacement two weekdays per week for each of >> 27 weeks (only 5 are shown). > > This seems simple enough, sampling without replacement. > > However, >> I need to sample from a sequence (3:7) that needs to be completely >> depleted and replenished until the >> final selection is made. Here is an example of what I want to do, >> beginning at WEEK 1. I would prefer to do >> this without using a loop, if possible. >> >> sample frame: [3,4,5,6,7] --> [4,5,6] --> [4],[1,2,3,(4),5,6] --> >> [1,2,4,5,6] --> for each WEEK in dataframe > > OK, now you have me completely lost. Sorry, but I have no clue as to what > you just did here. I looks like you are trying to describe some > transformation/algorithm but I don't follow it. > > > > I could not reply to this email because it not been delivered to my inbox, so > I had to copy it from the forum. > I apologize for the confusion, this would take less than a minute to explain > in conversation but an hour > to explain well in print. Two DOW_NUMs will be selected randomly without > replacement from the vector 3:7 for each WEEK. When this vector is reduced to > a single integer that integer will be selected and the vector will be > restored and a single integer will then be selected that differs from the > prior selected integer (i.e. cannot sample the same day twice in the same > week). This process will be repeated until two DOW_NUM have been assigned for > each WEEK. That process is what I attempted to illustrate in my original > message. This is beyond my current coding capabilities. > > > >> >> Randomly sample 2 DOW_NUM without replacement from each WEEK ( () = no two >> identical DOW_NUM can be sampled >> in the same WEEK) >> >> sample = {3,7}, {5,6}, {4,3}, {1,5}, --> for each WEEK in dataframe >> > > So, are you sampling from [3,4,5,6,7], or [1,2,4,5,6], or ...? Can you show > an 'example' of what you would like to end up given your data below? > >> >> Thanks you, >> >> Mike >> >> >> DATE DOW DOW_NUM WEEK >> 2 2011-05-02 Mon 3 1 >> 3 2011-05-03 Tue 4 1 >> 4 2011-05-04 Wed 5 1 >> 5 2011-05-05 Thu 6 1 >> 6 2011-05-06 Fri 7 1 >> 9 2011-05-09 Mon 3 2 >> 10 2011-05-10 Tue 4 2 >> 11 2011-05-11 Wed 5 2 >> 12 2011-05-12 Thu 6 2 >> 13 2011-05-13 Fri 7 2 >> 16 2011-05-16 Mon 3 3 >> 17 2011-05-17 Tue 4 3 >> 18 2011-05-18 Wed 5 3 >> 19 2011-05-19 Thu 6 3 >> 20 2011-05-20 Fri 7 3 >> 23 2011-05-23 Mon 3 4 >> 24 2011-05-24 Tue 4 4 >> 25 2011-05-25 Wed 5 4 >> 26 2011-05-26 Thu 6 4 >> 27 2011-05-27 Fri 7 4 >> 30 2011-05-30 Mon 3 5 >> 31 2011-05-31 Tue 4 5 >> 32 2011-06-01 Wed 5 5 >> 33 2011-06-02 Thu 6 5 >> 34 2011-06-03 Fri 7 5 >> >> DF <- >> structure(list(DATE = structure(c(15096, 15097, 15098, 15099, >> 15100, 15103, 15104, 15105, 15106, 15107, 15110, 15111, 15112, >> 15113, 15114, 15117, 15118, 15119, 15120, 15121, 15124, 15125, >> 15126, 15127, 15128), class = "Date"), DOW = c("Mon", "Tue", >> "Wed", "Thu", "Fri", "Mon", "Tue", "Wed", "Thu", "Fri", "Mon", >> "Tue", "Wed", "Thu", "Fri", "Mon", "Tue", "Wed", "Thu", "Fri", >> "Mon", "Tue", "Wed", "Thu", "Fri"), DOW_NUM = c(3, 4, 5, 6, 7, >> 3, 4, 5, 6, 7, 3, 4, 5, 6, 7, 3, 4, 5, 6, 7, 3, 4, 5, 6, 7), >> WEEK = c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, >> 4, 4, 4, 4, 5, 5, 5, 5, 5)), .Names = c("DATE", "DOW", "DOW_NUM", >> "WEEK"), row.names = c(2L, 3L, 4L, 5L, 6L, 9L, 10L, 11L, 12L, >> 13L, 16L, 17L, 18L, 19L, 20L, 23L, 24L, 25L, 26L, 27L, 30L, 31L, >> 32L, 33L, 34L), class = "data.frame") >> > > Dan > > Daniel Nordlund > Bothell, WA USA > > ______________________________________________ > 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. > > > > > message may contain confidential information. If you are not the designated > recipient, please notify the sender immediately, and delete the original and > any copies. Any use of the message by you is prohibited. > ______________________________________________ > 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. > -- Bert Gunter Genentech Nonclinical Biostatistics ______________________________________________ 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.
