Re: [R] match rows of R
On 26-06-2013, at 10:03, Sachinthaka Abeywardana sachin.abeyward...@gmail.com wrote: Hi all, What would be an efficient way to match rows of a matrix to a vector? ex: m-matrix(1:9, nrow=3) m [,1] [,2] [,3] [1,]147 [2,]258 [3,]369 # which(m==c(2,5,8))# I want this to return 2 ## Something like this: matroweqv - function(m,v) which(t(m)==v, arr.ind=TRUE)[,2][1] matroweqv(m,c(2,5,8)) # [1] 2 Berend __ 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.
Re: [R] match rows of R
I suggest using vectorization :
find_row - function(m,v) { which(!(abs(rowSums(m - rep(v, each = nrow(m)))
)) 0) }
The function matroweqv mentioned above would give any row with the first
element equal to the first element in vector v.
The function find_row matches each row of the matrix as a whole to the
vector v.
2013/6/26 Sachinthaka Abeywardana sachin.abeyward...@gmail.com
Hi all,
What would be an efficient way to match rows of a matrix to a vector?
ex:
m-matrix(1:9, nrow=3)
m [,1] [,2] [,3]
[1,]147
[2,]258
[3,]369
#
which(m==c(2,5,8))# I want this to return 2
##
Thanks,
Sachin
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--
Sincerely yours,
Yulia Matveyeva,
Department of Statistical Modelling,
Faculty of Mathematics and Mechanics,
St Petersburg State University, Russia
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Re: [R] match rows of R
On 26-06-2013, at 10:30, Yuliya Matveyeva yuliya.rm...@gmail.com wrote:
I suggest using vectorization :
find_row - function(m,v) { which(!(abs(rowSums(m - rep(v, each = nrow(m)))
)) 0) }
The function matroweqv mentioned above would give any row with the first
element equal to the first element in vector v.
Correct.
This version should be better
matroweqv - function(m,v) {
z - which(t(m)==v, arr.ind=TRUE,useNames=FALSE)
if(dim(z)[1]==0) return(NA) else if(all(z[,2]==z[1,2])) return(z[1,2])
else return(NA)
}
Instead of NA one could also return -1 if no row equals the vector.
Berend
The function find_row matches each row of the matrix as a whole to the
vector v.
2013/6/26 Sachinthaka Abeywardana sachin.abeyward...@gmail.com
Hi all,
What would be an efficient way to match rows of a matrix to a vector?
ex:
m-matrix(1:9, nrow=3)
m [,1] [,2] [,3]
[1,]147
[2,]258
[3,]369
#
which(m==c(2,5,8))# I want this to return 2
##
Thanks,
Sachin
[[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.
--
Sincerely yours,
Yulia Matveyeva,
Department of Statistical Modelling,
Faculty of Mathematics and Mechanics,
St Petersburg State University, Russia
[[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
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] match rows of R
Hi, Try: roweqv- function(m,v) which(!is.na(match(interaction(as.data.frame(m),drop=TRUE),paste(v,collapse=. v- c(2,5,8) roweqv(m,v) #[1] 2 set.seed(24) m1-matrix(sample(1:15,3e5,replace=TRUE),ncol=3) v1- c(10,12,4) system.time(res- roweqv(m1,v1)) # user system elapsed #0.132 0.000 0.130 res # [1] 5 381 2760 3793 9667 16881 18866 21219 24961 36220 38366 54382 #[13] 54951 55825 57167 67636 70713 71087 73284 82797 83255 85748 86216 86690 #[25] 93120 95399 96370 head(m1[res,]) # [,1] [,2] [,3] #[1,] 10 12 4 #[2,] 10 12 4 #[3,] 10 12 4 #[4,] 10 12 4 #[5,] 10 12 4 #[6,] 10 12 4 v2- c(20,5,4) roweqv(m1,v2) #integer(0) A.K. - Original Message - From: Sachinthaka Abeywardana sachin.abeyward...@gmail.com To: r-help@r-project.org r-help@r-project.org Cc: Sent: Wednesday, June 26, 2013 4:03 AM Subject: [R] match rows of R Hi all, What would be an efficient way to match rows of a matrix to a vector? ex: m-matrix(1:9, nrow=3) m [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 # which(m==c(2,5,8)) # I want this to return 2 ## Thanks, Sachin [[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.
Re: [R] match rows of R
This might also work:
roweqv2- function(m,v){indx-1+Reduce(+,lapply(seq_len(ncol(m)),function(i)
(2^i)*(m[,i]==v[i])))
which(indx==max(indx))}
roweqv2(m,v)
#[1] 2
system.time(res2-roweqv2(m1,v1))
# user system elapsed
#0.008 0.000 0.008
identical(res,res2)
#[1] TRUE
#On a bigger dataset
set.seed(248)
m1-matrix(sample(1:15,3e7,replace=TRUE),ncol=3)
v1- c(10,12,4)
system.time(res- roweqv(m1,v1))
# user system elapsed
# 12.404 1.248 13.677
system.time(res2-roweqv2(m1,v1))
# user system elapsed
# 0.760 0.312 1.076
identical(res,res2)
#[1] TRUE
A.K.
- Original Message -
From: arun smartpink...@yahoo.com
To: Sachinthaka Abeywardana sachin.abeyward...@gmail.com
Cc: R help r-help@r-project.org
Sent: Wednesday, June 26, 2013 3:26 PM
Subject: Re: [R] match rows of R
Hi,
Try:
roweqv- function(m,v)
which(!is.na(match(interaction(as.data.frame(m),drop=TRUE),paste(v,collapse=.
v- c(2,5,8)
roweqv(m,v)
#[1] 2
set.seed(24)
m1-matrix(sample(1:15,3e5,replace=TRUE),ncol=3)
v1- c(10,12,4)
system.time(res- roweqv(m1,v1))
# user system elapsed
#0.132 0.000 0.130
res
# [1] 5 381 2760 3793 9667 16881 18866 21219 24961 36220 38366 54382
#[13] 54951 55825 57167 67636 70713 71087 73284 82797 83255 85748 86216 86690
#[25] 93120 95399 96370
head(m1[res,])
# [,1] [,2] [,3]
#[1,] 10 12 4
#[2,] 10 12 4
#[3,] 10 12 4
#[4,] 10 12 4
#[5,] 10 12 4
#[6,] 10 12 4
v2- c(20,5,4)
roweqv(m1,v2)
#integer(0)
A.K.
- Original Message -
From: Sachinthaka Abeywardana sachin.abeyward...@gmail.com
To: r-help@r-project.org r-help@r-project.org
Cc:
Sent: Wednesday, June 26, 2013 4:03 AM
Subject: [R] match rows of R
Hi all,
What would be an efficient way to match rows of a matrix to a vector?
ex:
m-matrix(1:9, nrow=3)
m [,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
#
which(m==c(2,5,8)) # I want this to return 2
##
Thanks,
Sachin
[[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.
