[R] mirror vector?
Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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.
Re: [R] mirror vector?
mat - matrix(1:16,4,4) mat [,1] [,2] [,3] [,4] [1,]159 13 [2,]26 10 14 [3,]37 11 15 [4,]48 12 16 apply(mat,2,rev) [,1] [,2] [,3] [,4] [1,]48 12 16 [2,]37 11 15 [3,]26 10 14 [4,]159 13 --- Jacques VESLOT CNRS UMR 8090 I.B.L (2ème étage) 1 rue du Professeur Calmette B.P. 245 59019 Lille Cedex Tel : 33 (0)3.20.87.10.44 Fax : 33 (0)3.20.87.10.31 http://www-good.ibl.fr --- [EMAIL PROTECTED] a écrit : Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
Re: [R] mirror vector?
Hi Antje use the fact that n:1 counts backwards from n, and then use this as a row index: m - matrix(1:30,5,6) m[nrow(m):1,] [,1] [,2] [,3] [,4] [,5] [,6] [1,]5 10 15 20 25 30 [2,]49 14 19 24 29 [3,]38 13 18 23 28 [4,]27 12 17 22 27 [5,]16 11 16 21 26 [ a more general answer would be library(magic) arev(m,1) ] HTH rksh On 28 Jul 2006, at 08:50, [EMAIL PROTECTED] wrote: Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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. -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 __ R-help@stat.math.ethz.ch 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.
Re: [R] mirror vector?
Hi Not that there's anything wrong with Jacques's answer, but the List might be interested in the following gotcha: m - matrix(1:30,5,6) apply(m,2,rev) [,1] [,2] [,3] [,4] [,5] [,6] [1,]5 10 15 20 25 30 [2,]49 14 19 24 29 [3,]38 13 18 23 28 [4,]27 12 17 22 27 [5,]16 11 16 21 26 apply(m,1,rev) [,1] [,2] [,3] [,4] [,5] [1,] 26 27 28 29 30 [2,] 21 22 23 24 25 [3,] 16 17 18 19 20 [4,] 11 12 13 14 15 [5,]6789 10 [6,]12345 See how the first usage of apply() works as expected (at least for me ;-) but the second returns the transpose of what one might need. That's why I wrote arev(). comments anyone? On 28 Jul 2006, at 08:56, Jacques VESLOT wrote: mat - matrix(1:16,4,4) mat [,1] [,2] [,3] [,4] [1,]159 13 [2,]26 10 14 [3,]37 11 15 [4,]48 12 16 apply(mat,2,rev) [,1] [,2] [,3] [,4] [1,]48 12 16 [2,]37 11 15 [3,]26 10 14 [4,]159 13 --- Jacques VESLOT CNRS UMR 8090 I.B.L (2ème étage) 1 rue du Professeur Calmette B.P. 245 59019 Lille Cedex Tel : 33 (0)3.20.87.10.44 Fax : 33 (0)3.20.87.10.31 http://www-good.ibl.fr --- [EMAIL PROTECTED] a écrit : Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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. -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 __ R-help@stat.math.ethz.ch 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.
Re: [R] mirror vector?
Jacques VESLOT wrote: mat - matrix(1:16,4,4) mat [,1] [,2] [,3] [,4] [1,]159 13 [2,]26 10 14 [3,]37 11 15 [4,]48 12 16 apply(mat,2,rev) [,1] [,2] [,3] [,4] [1,]48 12 16 [2,]37 11 15 [3,]26 10 14 [4,]159 13 or a lot faster: mat[nrow(mat):1, ] Uwe Ligges --- Jacques VESLOT CNRS UMR 8090 I.B.L (2ème étage) 1 rue du Professeur Calmette B.P. 245 59019 Lille Cedex Tel : 33 (0)3.20.87.10.44 Fax : 33 (0)3.20.87.10.31 http://www-good.ibl.fr --- [EMAIL PROTECTED] a écrit : Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
Re: [R] mirror vector?
Another approach is: mat[nrow(mat):1, ] Patrick Burns [EMAIL PROTECTED] +44 (0)20 8525 0696 http://www.burns-stat.com (home of S Poetry and A Guide for the Unwilling S User) Jacques VESLOT wrote: mat - matrix(1:16,4,4) mat [,1] [,2] [,3] [,4] [1,]159 13 [2,]26 10 14 [3,]37 11 15 [4,]48 12 16 apply(mat,2,rev) [,1] [,2] [,3] [,4] [1,]48 12 16 [2,]37 11 15 [3,]26 10 14 [4,]159 13 --- Jacques VESLOT CNRS UMR 8090 I.B.L (2ème étage) 1 rue du Professeur Calmette B.P. 245 59019 Lille Cedex Tel : 33 (0)3.20.87.10.44 Fax : 33 (0)3.20.87.10.31 http://www-good.ibl.fr --- [EMAIL PROTECTED] a écrit : Hello, I'm an absolut beginner with R and now I got a 2D vector with numbers. I would like to mirror this vector now by the rows (so that the first row becomes last, second becomes one before last, ...). I don't know if there is any method I can use to do this. Could you please help me? Antje - Was Sie schon immer wissen wollten aber nie zu Fragen trauten? Yahoo! Clever hilft Ihnen. [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
