Re: [R] Counting zeros in a matrix
rowSums((A[,1:8]==0)*A[,2:9]==1) and adjust the 8 and the 9 for the number of columns in your matrix Ben -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Guenther, Cameron Sent: Tuesday, November 28, 2006 3:20 PM To: [email protected] Subject: [R] Counting zeros in a matrix Hi All, If you could help me with this problem I would greatly appreciate it. Suppose I have a matrix A: 1 1 1 1 0 1 1 1 1 1 1 1 0 1 0 1 0 0 1 0 1 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 I would like, for each row, to sum the number of times a 0 appears in front of a 1. So what I would like is to have Sum 1 1 1 1 0 1 1 1 1 1 1 1 1 0 1 0 1 0 0 2 1 0 1 0 0 1 0 0 0 2 1 1 0 0 0 0 1 0 0 1 I tried writing a function to do this but am getting mixed up in the [i,j] coding. This is just an example the real matrix is much larger. Thanks in advance. Cameron Guenther, Ph.D. 100 8th Ave. SE St. Petersburg, Fl 33701 727-896-8626 ext. 4305 [EMAIL PROTECTED] __ [email protected] 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] Counting zeros in a matrix
countZerosBeforeOnes <- function(v) sum(v[1:max(which(v == 1))] == 0) apply(A, 1, countZerosBeforeOnes) cheers, b On Nov 28, 2006, at 4:20 PM, Guenther, Cameron wrote: > Hi All, > > If you could help me with this problem I would greatly appreciate it. > > Suppose I have a matrix A: > > 1 1 1 1 0 1 1 1 1 > 1 1 1 0 1 0 1 0 0 > 1 0 1 0 0 1 0 0 0 > 1 1 0 0 0 0 1 0 0 > > I would like, for each row, to sum the number of times a 0 appears in > front of a 1. So what I would like is to have >Sum > 1 1 1 1 0 1 1 1 1 1 > 1 1 1 0 1 0 1 0 0 2 > 1 0 1 0 0 1 0 0 0 2 > 1 1 0 0 0 0 1 0 0 1 > > I tried writing a function to do this but am getting mixed up in the > [i,j] coding. This is just an example the real matrix is much larger. > > Thanks in advance. > > > > Cameron Guenther, Ph.D. > 100 8th Ave. SE > St. Petersburg, Fl 33701 > 727-896-8626 ext. 4305 > [EMAIL PROTECTED] > __ > [email protected] 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. __ [email protected] 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] Counting zeros in a matrix
A <- matrix(c( 1,1,1,1,0,1,1,1,1, 1,1,1,0,1,0,1,0,0, 1,0,1,0,0,1,0,0,0, 1,1,0,0,0,0,1,0,0), 4, 9, byrow=TRUE) apply(A, 1, function(x) sum(diff(x)==1)) __ [email protected] 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] Counting zeros in a matrix
On Tue, 2006-11-28 at 16:20 -0500, Guenther, Cameron wrote: > Hi All, > > If you could help me with this problem I would greatly appreciate it. > > Suppose I have a matrix A: > > 1 1 1 1 0 1 1 1 1 > 1 1 1 0 1 0 1 0 0 > 1 0 1 0 0 1 0 0 0 > 1 1 0 0 0 0 1 0 0 > > I would like, for each row, to sum the number of times a 0 appears in > front of a 1. So what I would like is to have >Sum > 1 1 1 1 0 1 1 1 1 1 > 1 1 1 0 1 0 1 0 0 2 > 1 0 1 0 0 1 0 0 0 2 > 1 1 0 0 0 0 1 0 0 1 > > I tried writing a function to do this but am getting mixed up in the > [i,j] coding. This is just an example the real matrix is much larger. > > Thanks in advance. Not fully tested, but how about this: > mat [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] 1111101111 2111010100 3101001000 4110000100 > cbind(mat, colSums(apply(mat, 1, diff) == 1)) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] 1111101111 1 2111010100 2 3101001000 2 4110000100 1 HTH, Marc Schwartz __ [email protected] 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] Counting zeros in a matrix
temp<-apply(A,1,sum(diff(x)) == -1 ) but check it because I haven't tested it and when things are not tested there can often be unforeseen problems. Also, may have to declare sum(diff(x)) == -1 as a separate function and then call it. I'm not sure aobut that. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Guenther, Cameron Sent: Tuesday, November 28, 2006 4:20 PM To: [email protected] Subject: [R] Counting zeros in a matrix Hi All, If you could help me with this problem I would greatly appreciate it. Suppose I have a matrix A: 1 1 1 1 0 1 1 1 1 1 1 1 0 1 0 1 0 0 1 0 1 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 I would like, for each row, to sum the number of times a 0 appears in front of a 1. So what I would like is to have Sum 1 1 1 1 0 1 1 1 1 1 1 1 1 0 1 0 1 0 0 2 1 0 1 0 0 1 0 0 0 2 1 1 0 0 0 0 1 0 0 1 I tried writing a function to do this but am getting mixed up in the [i,j] coding. This is just an example the real matrix is much larger. Thanks in advance. Cameron Guenther, Ph.D. 100 8th Ave. SE St. Petersburg, Fl 33701 727-896-8626 ext. 4305 [EMAIL PROTECTED] This is not an offer (or solicitation of an offer) to buy/se...{{dropped}} __ [email protected] 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.
