HI, The option z5 takes care of it. z5<-t(x-t(mat)) #still faster than ?sweep() dim(z5) [1] 20 2 identical(sweep(-mat,2,x,"+"),z5) #[1] TRUE
A.K. ________________________________ From: C W <tmrs...@gmail.com> To: arun <smartpink...@yahoo.com> Sent: Wednesday, December 5, 2012 5:09 PM Subject: Re: [R] data manipulation between vector and matrix Hi Arun, Sorry, I might be a little unclear with my words. The dimensions are different. This is what I got: > x-t(mat) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [1,] 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 [2,] -19 -20 -21 -22 -23 -24 -25 -26 -27 -28 -29 -30 -31 -32 [,15] [,16] [,17] [,18] [,19] [,20] [1,] -14 -15 -16 -17 -18 -19 [2,] -33 -34 -35 -36 -37 -38 > sweep(-mat, 2, x, "+") [,1] [,2] [1,] 0 -19 [2,] -1 -20 [3,] -2 -21 [4,] -3 -22 [5,] -4 -23 [6,] -5 -24 [7,] -6 -25 [8,] -7 -26 [9,] -8 -27 [10,] -9 -28 [11,] -10 -29 [12,] -11 -30 [13,] -12 -31 [14,] -13 -32 [15,] -14 -33 [16,] -15 -34 [17,] -16 -35 [18,] -17 -36 [19,] -18 -37 [20,] -19 -38 > dim(x-t(mat)) [1] 2 20 > dim(sweep(-mat, 2, x, "+")) [1] 20 2 On Wed, Dec 5, 2012 at 4:55 PM, arun <smartpink...@yahoo.com> wrote: HI Mike, >I didn't understand "except the x-t(mat) output is very different than the >others". Are you saying that it needs to be transposed? BTW, that was z5. > >A.K. > > > > > > > >________________________________ >From: C W <tmrs...@gmail.com> >To: arun <smartpink...@yahoo.com> >Cc: R help <r-help@r-project.org>; Sarah Goslee <sarah.gos...@gmail.com> >Sent: Wednesday, December 5, 2012 4:47 PM > >Subject: Re: [R] data manipulation between vector and matrix > > >Thanks for the benchmark. I actually wanted to go with the winner, except the >x-t(mat) output is very different than the others. >Mike > > >On Wed, Dec 5, 2012 at 4:40 PM, arun <smartpink...@yahoo.com> wrote: > >Hi, >> >>By comparing the different methods: >>set.seed(5) >> mat1<-matrix(sample(1:1e6,1e6,replace=TRUE),ncol=10000) >> set.seed(25) >> x<-sample(1:1e6,10000,replace=TRUE) >> system.time(z1<-sweep(-mat1,2,x,"+")) >># user system elapsed >> # 0.076 0.000 0.069 >> system.time(z2<-apply(-mat1,1,`+`,x)) >> # user system elapsed >> # 0.036 0.000 0.031 >> system.time(z3<-aaply(-mat1,1,`+`,x)) >># user system elapsed >># 1.880 0.000 1.704 >> system.time(z4<- x-t(mat1)) #winner >># user system elapsed >> # 0.004 0.000 0.007 >> system.time(z5<- t(x-t(mat1))) >># user system elapsed >># 0.008 0.000 0.009 >> >> >>A.K. >> >> >> >> >> >> >>________________________________ >>From: C W <tmrs...@gmail.com> >>To: arun <smartpink...@yahoo.com> >>Cc: R help <r-help@r-project.org>; Sarah Goslee <sarah.gos...@gmail.com> >>Sent: Wednesday, December 5, 2012 4:11 PM >> >>Subject: Re: [R] data manipulation between vector and matrix >> >> >>thanks, I knew about apply, but did not you you can put plus signs with >>quotes. That's a cool tricky, >>Mike >> >> >>On Wed, Dec 5, 2012 at 4:05 PM, arun <smartpink...@yahoo.com> wrote: >> >>HI, >>>In addition to ?sweep(), you can use >>> >>>apply(-mat,1,`+`,x) >>> >>>#or >>>library(plyr) >>>aaply(-mat,1,"+",x) >>> >>> >>>A.K. >>> >>> >>> >>> >>> >>> >>> >>>----- Original Message ----- >>>From: C W <tmrs...@gmail.com> >>>To: Sarah Goslee <sarah.gos...@gmail.com> >>>Cc: r-help <r-help@r-project.org> >>>Sent: Wednesday, December 5, 2012 1:51 PM >>>Subject: Re: [R] data manipulation between vector and matrix >>> >>>Thanks, Sarah. First time heard about sweep(), it worked just the way I >>>wanted. >>>Mike >>> >>>On Wed, Dec 5, 2012 at 1:42 PM, Sarah Goslee <sarah.gos...@gmail.com> wrote: >>> >>>> Hi, >>>> >>>> On Wed, Dec 5, 2012 at 1:30 PM, C W <tmrs...@gmail.com> wrote: >>>> > Dear list, >>>> > I was curious how to subtract a vector from matrix? >>>> > >>>> > Say, I have >>>> > >>>> > mat <- matrix(1:40, nrow=20, ncol=2) >>>> > >>>> > x <-c(1,2) >>>> >>>> Thanks for the actual reproducible example. >>>> >>>> > I want, >>>> > >>>> > x-mat[1,] and x-mat[2,], and so on... Basically, subtract column elements >>>> > of x against column elements in mat. >>>> > >>>> > But x-mat won't do it. >>>> >>>> This will (note the modification to get x - mat): >>>> > sweep(-mat, 2, x, "+") >>>> [,1] [,2] >>>> [1,] 0 -19 >>>> [2,] -1 -20 >>>> [3,] -2 -21 >>>> [4,] -3 -22 >>>> [5,] -4 -23 >>>> etc. >>>> >>>> -- >>>> Sarah Goslee >>>> http://www.functionaldiversity.org >>>> >>> >>> [[alternative HTML version deleted]] >>> >>>______________________________________________ >>>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.
