Re: [R] matrix indexing/subset error

2016-05-30 Thread Jeff Newmiller
z %% 2 == 1 has 12 logical values. What do you expect R to do with it worth respect to 4 rows? -- Sent from my phone. Please excuse my brevity. On May 30, 2016 11:38:46 AM PDT, Carl Sutton via R-help wrote: >Hi Guru's >In my quest to understand R I have what I thought was a simple exercise

Re: [R] matrix indexing (igraph ?)

2011-08-18 Thread Gábor Csárdi
This is not an igraph issue, I believe. You need to go over your indices and update the matrix, i.e. for (i in seq_along(t.list)) { temp[t.list[i], c.list[i]] <- temp[t.list[i], c.list[i]] + 1 } Best, Gabor On Tue, Aug 2, 2011 at 4:50 PM, Robinson, David G wrote: > I realize that matrix indexin

Re: [R] matrix indexing in 'for' loop?

2010-12-22 Thread govindas
Thank you all once again .. Yeah, its working now. -- Regards, Mahalakshmi Graduate Student #20, Department of Geography Michigan State University East Lansing, MI 48824 Quoting Liviu Andronic : > On Wed, Dec 22, 2010 at 6:39 PM,  wrote: >> Thank you both for your suggestions. I have anothe

Re: [R] matrix indexing in 'for' loop?

2010-12-22 Thread Bert Gunter
Have you consulted R's extensive documentation? -- in particular, "An Introduction to R," which would seem like an obvious place for R newbies to start. If you had done so, you would have found your question answered there in section 6.1 on lists. -- Bert Gunter On Wed, Dec 22, 2010 at 9:39 AM,

Re: [R] matrix indexing in 'for' loop?

2010-12-22 Thread Liviu Andronic
On Wed, Dec 22, 2010 at 6:39 PM, wrote: > Thank you both for your suggestions. I have another question - is there a > specific way to access the individual elements of a 'list' variable? i.e. > > dmi = matrix(rnorm(20),4,5) > soi = matrix(rnorm(20),4,5) > pe = matrix(rnorm(20),4,5) > y <- list(dm

Re: [R] matrix indexing in 'for' loop?

2010-12-22 Thread govindas
Thank you both for your suggestions. I have another question - is there a specific way to access the individual elements of a 'list' variable? i.e.  dmi = matrix(rnorm(20),4,5) soi = matrix(rnorm(20),4,5) pe = matrix(rnorm(20),4,5) y <- list(dmi, soi, pe) y[[1]]   gives [,1]       [,2

Re: [R] matrix indexing in 'for' loop?

2010-12-22 Thread Liviu Andronic
On Wed, Dec 22, 2010 at 2:57 AM, Phil Spector wrote: > To make your loop work, you need to learn about the get function. > I'm not going to give you the details because there are better > approaches available. > First, let's make some data that will give values which can be verified. >  (All the c

Re: [R] matrix indexing in 'for' loop?

2010-12-21 Thread Phil Spector
To make your loop work, you need to learn about the get function. I'm not going to give you the details because there are better approaches available. First, let's make some data that will give values which can be verified. (All the correlations of the data you created are exactly equal to 1.)

Re: [R] matrix indexing and update

2008-11-05 Thread Jorge Ivan Velez
Dear Murali, Here is one way: set.seed(123) a <- matrix(abs(rnorm(100)), 10) b <- rnorm(10) apply(a,2,function(x) ifelse(b>quantile(b,probs=0.75),-x,x)) HTH, Jorge On Wed, Nov 5, 2008 at 11:30 AM, <[EMAIL PROTECTED]> wrote: > Folks, > > I have a matrix: > > set.seed(123) > a <- matrix(rn

Re: [R] matrix indexing and update

2008-11-05 Thread Dimitris Rizopoulos
you almost have it, e.g., check the following: set.seed(123) a <- matrix(rnorm(100), 10) b <- rnorm(10) ind <- b > quantile(b, 0.75) a[ind, ] <- -a[ind, ] a I hope it helps. Best, Dimitris [EMAIL PROTECTED] wrote: Folks, I have a matrix: set.seed(123) a <- matrix(rnorm(100), 10) And a v

Re: [R] Matrix Indexing

2008-04-12 Thread Duncan Murdoch
Rory Winston wrote: > Hi > > Does anyone know how I might pick out diagonal elements of a matrix using a > vector? > > If I create a matrix a: > > a <- matrix(c(1:16), 4, byrow=TRUE) > > and I want to pick out the elements (1,1),(2,2),(3,3), or another arbitrary > diagonal (upper or lower), is ther

Re: [R] Matrix Indexing

2008-04-12 Thread Gavin Simpson
On Sat, 2008-04-12 at 10:56 +0100, Rory Winston wrote: > Hi > > Does anyone know how I might pick out diagonal elements of a matrix using a > vector? > > If I create a matrix a: > > a <- matrix(c(1:16), 4, byrow=TRUE) Not sure if this does all that you describe below, but: diag(a) and you can

Re: [R] Matrix Indexing

2008-04-12 Thread Chuck Cleland
On 4/12/2008 5:56 AM, Rory Winston wrote: > Hi > > Does anyone know how I might pick out diagonal elements of a matrix using a > vector? > > If I create a matrix a: > > a <- matrix(c(1:16), 4, byrow=TRUE) > > and I want to pick out the elements (1,1),(2,2),(3,3), or another arbitrary > diagonal