Hi Paul, Wonder why this is an R devel thing?
ifelse is vectorized----there should be logical conditions matching the length of the output. ifelse(c(1, 1, 1), list(a=2, b=3, c=4), list(d=1, e=2, f=3)) otherwise it is truncated. Also note that both results have to be valid, because both are typically evaluated. Cheers, Josh On Sun, Mar 24, 2013 at 7:21 PM, Paul Johnson <pauljoh...@gmail.com> wrote: > I hope you are doing well. > > For me, this was an unexpected problem. I've hoped for quite a few > wrong things today, but I'm only asking you about this one. Why does > > ifelse(1, list(a, b, c), list(x, y, z)) > > return a list with only a, not list(a, b, c) as I hoped. I wish it > would either > cause an error or return the whole list, not just the first thing. > > Working example: > >> x <- 1 >> y <- 2 >> z <- 3 >> a <- 4 >> b <- 5 >> c <- 6 >> list(x,y,z) > [[1]] > [1] 1 > > [[2]] > [1] 2 > > [[3]] > [1] 3 > >> list(a,b,c) > [[1]] > [1] 4 > > [[2]] > [1] 5 > > [[3]] > [1] 6 > >> ifelse(1, list(a,b,c), list(x,y,z)) > [[1]] > [1] 4 > >> ifelse(0, list(a,b,c), list(x,y,z)) > [[1]] > [1] 1 > > >> sessionInfo() > R version 2.15.3 (2013-03-01) > Platform: x86_64-pc-linux-gnu (64-bit) > > locale: > [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C > [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 > [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 > [7] LC_PAPER=C LC_NAME=C > [9] LC_ADDRESS=C LC_TELEPHONE=C > [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > other attached packages: > [1] rockchalk_1.5.5.10 car_2.0-16 nnet_7.3-5 MASS_7.3-23 > > loaded via a namespace (and not attached): > [1] compiler_2.15.3 tools_2.15.3 > > > I realize I can code around this, but I'm just curious about why > ifelse hates me so much :( > >> if (1) myvar <- list(a, b, c) else myvar <- list(x, y, z) >> myvar > [[1]] > [1] 4 > > [[2]] > [1] 5 > > [[3]] > [1] 6 > >> myvar <- if (1) list(a, b, c) else list(x, y, z) >> myvar > [[1]] > [1] 4 > > [[2]] > [1] 5 > > [[3]] > [1] 6 > > > -- > Paul E. Johnson > Professor, Political Science Assoc. Director > 1541 Lilac Lane, Room 504 Center for Research Methods > University of Kansas University of Kansas > http://pj.freefaculty.org http://quant.ku.edu > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://joshuawiley.com/ Senior Analyst - Elkhart Group Ltd. http://elkhartgroup.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
