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
cameron.guenther at myfwc.com
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: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Guenther, Cameron
Sent: Tuesday, November 28, 2006 4:20 PM
To: r-help at stat.math.ethz.ch
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
cameron.guenther at myfwc.com
--------------------------------------------------------
This is not an offer (or solicitation of an offer) to buy/se...{{dropped}}
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] 1 1 1 1 1 0 1 1 1 1 2 1 1 1 0 1 0 1 0 0 3 1 0 1 0 0 1 0 0 0 4 1 1 0 0 0 0 1 0 0> cbind(mat, colSums(apply(mat, 1, diff) == 1))[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] 1 1 1 1 1 0 1 1 1 1 1 2 1 1 1 0 1 0 1 0 0 2 3 1 0 1 0 0 1 0 0 0 2 4 1 1 0 0 0 0 1 0 0 1 HTH, Marc Schwartz
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))
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 > cameron.guenther at myfwc.com > ______________________________________________ > R-help at 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.
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: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Guenther, Cameron
Sent: Tuesday, November 28, 2006 3:20 PM
To: r-help at stat.math.ethz.ch
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
cameron.guenther at myfwc.com