2011/9/6 Jean-Christophe BOUËTTÉ <jcboue...@gmail.com>: you could tapply function(x) if(length(x)==1) x else sample(x) or something like this > > 2011/9/6 Jean-Christophe BOUËTTÉ <jcboue...@gmail.com>: >> Hi there, >> in the third case you get sample(5) which is exactly what you asked for. >> >> from ?sample: >> "If x has length 1, is numeric (in the sense of is.numeric) and x >= >> 1, sampling via sample takes place from 1:x. Note that this >> convenience feature may lead to undesired behaviour when x is of >> varying length in calls such as sample(x). See the examples. " >> >> 2011/9/6 Jack Siegrist <jack...@eden.rutgers.edu>: >>> I want to sample within groups, and when a group has only one associated >>> number to just return that number. >>> >>> If I use this code: >>> >>> groups <- c(1, 2, 2, 2, 3) >>> numbers <- 1:5 >>> tapply(numbers, groups, FUN = sample) >>> >>> I get the following output: >>> >>>> groups <- c(1, 2, 2, 2, 3) >>>> numbers <- 1:5 >>>> tapply(numbers, groups, FUN = sample) >>> $`1` >>> [1] 1 >>> >>> $`2` >>> [1] 3 2 4 >>> >>> $`3` >>> [1] 2 3 5 1 4 >>> >>> Can someone tell me why the $'3' result samples all of the numbers and how >>> to prevent it from doing so? I want the output for the $'3' part to just be >>> 5 in this example. >>> >>> Thanks for your help. >>> >>> >>>> sessionInfo() >>> R version 2.11.1 (2010-05-31) >>> i386-pc-mingw32 >>> >>> -- >>> View this message in context: >>> http://r.789695.n4.nabble.com/sample-within-groups-slight-problem-tp3794912p3794912.html >>> Sent from the R help mailing list archive at Nabble.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. >>> >> >
______________________________________________ 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.
