This is one of those instances where a less superficial knowledge of R's technical details comes in really handy.
What you need to do is convert the data frame to a single (numeric) vector for, e.g. a matrix() call. This can be easily done by noting that a data frame is also a list and using do.call(): ## imp is the data frame: do.call(c,imp) X11 X12 X13 X14 X15 X16 X17 X18 X19 X110 X111 X112 X113 X114 1 2 1 2 1 2 1 2 1 2 1 2 1 2 X115 X116 X21 X22 X23 X24 X25 X26 X27 X28 X29 X210 X211 X212 1 2 0 1 0 1 1 1 0 1 0 1 0 1 X213 X214 X215 X216 Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y10 1 1 0 1 1 2 3 4 5 6 7 8 1 2 Y11 Y12 Y13 Y14 Y15 Y16 3 4 5 6 7 8 So, e.g. for a 3 column matrix: > matrix(do.call(c,imp), ncol=3) [,1] [,2] [,3] [1,] 1 0 1 [2,] 2 1 2 [3,] 1 0 3 [4,] 2 1 4 [5,] 1 1 5 [6,] 2 1 6 [7,] 1 0 7 [8,] 2 1 8 [9,] 1 0 1 [10,] 2 1 2 [11,] 1 0 3 [12,] 2 1 4 [13,] 1 1 5 [14,] 2 1 6 [15,] 1 0 7 [16,] 2 1 8 Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Thu, May 24, 2018 at 7:46 AM, Ioanna Ioannou <ii54...@msn.com> wrote: > Hello everyone, > > > I want to transform a data.frame into an array (lets call it mydata), > where: mydata[[1]] is the first imputed dataset...and for each mydata[[d]], > the first p columns are covariates X, and the last one is the outcome Y. > > > Lets assume a simple data.frame: > > > Imputed = data.frame( X1 = c(1,2,1,2,1,2,1,2, 1,2,1,2,1,2,1,2), > > X2 = c(0,1,0,1,1,1,0,1, > 0,1,0,1,1,1,0,1), > > Y = > c(1,2,3,4,5,6,7,8,1,2,3,4,5,6,7,8)) > > The first 8 have been obtained by the first imputation and the later 8 by > the 2nd. > > > Can you help me please? > > > Best, > > ioanna > > [[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. > [[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.