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.
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?
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?
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?
> 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.
