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Steven Kang

2009-Aug-27 06:13 UTC

[R] Help on efficiency/vectorization

Dear R users,

I am trying to extract the rownames of a data set for which each columns
meet a certain criteria. (condition - elements of each column to be equal
1)

I have the correct result, however I am seeking for more efficient (desire
vectorization) way in implementing such problem as it can get quite messy if
there are hundreds of columns.

Arbitrary data set and codes are shown below for your reference:

x <- as.data.frame(matrix(round(runif(50),0),nrow=5))

rownames(x) <- letters[1:dim(x)[1]]
> x  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
a  0  1   1    1   0   0    0   0   1    0
b  1  1   1    1   0   1    0   0   1    1
c  0  1   1    0   0   0    0   0   0    1
d  1  0   0    1   1   1    1   1   0    0
e  1  0   0    0   0   1    1   0   1    0

V1.ind <- rownames(x)[x[,"V1"]==1]
V2.ind <- rownames(x)[x[,"V2"]==1]
V3.ind <- rownames(x)[x[,"V3"]==1]
V4.ind <- rownames(x)[x[,"V4"]==1]
:
:
V10.ind <- rownames(x)[x[,"V10"]==1]
> V1.ind
[1] "b" "d" "e"> V2.ind
[1] "a" "b" "c"> V3.ind[1] "a" "b" "c"
:
:> V10.ind[1] "b" "c"



Your expertise in resolving this issue would be highly appreciated.


Steve

	[[alternative HTML version deleted]]

Gerrit Eichner

2009-Aug-27 06:32 UTC

head link

[R] Help on efficiency/vectorization

Hi, Steven,

try

lapply( x, function( v) rownames(x)[ v == 1])

or

lapply( x, function( v, rn) rn[ v == 1], rn = rownames( x)))

which is faster.

  Regards  --  Gerrit

---------------------------------------------------------------------
AOR Dr. Gerrit Eichner             Mathematical Institute, Room 305 E
gerrit.eichner at math.uni-giessen.de   Justus-Liebig-University Giessen
Tel: +49-(0)641-99-32104          Arndtstr. 2, 35392 Giessen, Germany
Fax: +49-(0)641-99-32109              http://www.uni-giessen.de/~gcb7
---------------------------------------------------------------------

On Thu, 27 Aug 2009, Steven Kang wrote:
> Dear R users,
> 
> I am trying to extract the rownames of a data set for which each columns
> meet a certain criteria. (condition - elements of each column to be equal
> 1)
> 
> I have the correct result, however I am seeking for more efficient (desire
> vectorization) way in implementing such problem as it can get quite messy
> if
> there are hundreds of columns.
> 
> Arbitrary data set and codes are shown below for your reference:
> 
> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
> 
> rownames(x) <- letters[1:dim(x)[1]]
> 
> > x
>  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
> a  0  1   1    1   0   0    0   0   1    0
> b  1  1   1    1   0   1    0   0   1    1
> c  0  1   1    0   0   0    0   0   0    1
> d  1  0   0    1   1   1    1   1   0    0
> e  1  0   0    0   0   1    1   0   1    0
> 
> V1.ind <- rownames(x)[x[,"V1"]==1]
> V2.ind <- rownames(x)[x[,"V2"]==1]
> V3.ind <- rownames(x)[x[,"V3"]==1]
> V4.ind <- rownames(x)[x[,"V4"]==1]
> :
> :
> V10.ind <- rownames(x)[x[,"V10"]==1]
> 
> > V1.ind
> [1] "b" "d" "e"
> > V2.ind
> [1] "a" "b" "c"
> > V3.ind
> [1] "a" "b" "c"
> :
> :
> > V10.ind
> [1] "b" "c"
> 
> 
> 
> Your expertise in resolving this issue would be highly appreciated.
> 
> 
> Steve
>
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.
>

Moshe Olshansky

2009-Aug-27 06:36 UTC

head link

[R] Help on efficiency/vectorization

You can do

for (i in 1:ncol(x)) {names <-
rownames(x)[which(x[,i]==1)];eval(parse(text=paste("V",i,".ind<-names",sep="")));}



--- On Thu, 27/8/09, Steven Kang <stochastickang at gmail.com> wrote:
> From: Steven Kang <stochastickang at gmail.com>
> Subject: [R] Help on efficiency/vectorization
> To: r-help at r-project.org
> Received: Thursday, 27 August, 2009, 4:13 PM
> Dear R users,
> 
> I am trying to extract the rownames of a data set for which
> each columns
> meet a certain criteria. (condition - elements of each
> column to be equal
> 1)
> 
> I have the correct result, however I am seeking for more
> efficient (desire
> vectorization) way in implementing such problem as it can
> get quite messy if
> there are hundreds of columns.
> 
> Arbitrary data set and codes are shown below for your
> reference:
> 
> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
> 
> rownames(x) <- letters[1:dim(x)[1]]
> 
> > x
> ? V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
> a? 0? 1???1? ?
> 1???0???0? ?
> 0???0???1? ? 0
> b? 1? 1???1? ?
> 1???0???1? ?
> 0???0???1? ? 1
> c? 0? 1???1? ?
> 0???0???0? ?
> 0???0???0? ? 1
> d? 1? 0???0? ?
> 1???1???1? ?
> 1???1???0? ? 0
> e? 1? 0???0? ?
> 0???0???1? ?
> 1???0???1? ? 0
> 
> V1.ind <- rownames(x)[x[,"V1"]==1]
> V2.ind <- rownames(x)[x[,"V2"]==1]
> V3.ind <- rownames(x)[x[,"V3"]==1]
> V4.ind <- rownames(x)[x[,"V4"]==1]
> :
> :
> V10.ind <- rownames(x)[x[,"V10"]==1]
> 
> > V1.ind
> [1] "b" "d" "e"
> > V2.ind
> [1] "a" "b" "c"
> > V3.ind
> [1] "a" "b" "c"
> :
> :
> > V10.ind
> [1] "b" "c"
> 
> 
> 
> Your expertise in resolving this issue would be highly
> appreciated.
> 
> 
> Steve
> 
> ??? [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.
>

jim holtman

2009-Aug-27 12:03 UTC

head link

[R] Help on efficiency/vectorization

try this:
> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
> rownames(x) <- letters[1:dim(x)[1]]
> x  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
a  0  0  1  0  0  1  0  0  0   1
b  1  0  0  0  1  1  1  1  0   0
c  0  1  0  1  0  0  0  0  1   0
d  0  1  0  0  0  1  0  0  1   1
e  0  0  1  1  0  1  1  0  1   1> lapply(names(x), function(z) rownames(x)[x[[z]] == 1])[[1]]
[1] "b"

[[2]]
[1] "c" "d"

[[3]]
[1] "a" "e"

[[4]]
[1] "c" "e"

[[5]]
[1] "b"

[[6]]
[1] "a" "b" "d" "e"

[[7]]
[1] "b" "e"

[[8]]
[1] "b"

[[9]]
[1] "c" "d" "e"

[[10]]
[1] "a" "d" "e"
>

On Thu, Aug 27, 2009 at 2:13 AM, Steven Kang<stochastickang at gmail.com>
wrote:> Dear R users,
>
> I am trying to extract the rownames of a data set for which each columns
> meet a certain criteria. (condition - elements of each column to be equal
> 1)
>
> I have the correct result, however I am seeking for more efficient (desire
> vectorization) way in implementing such problem as it can get quite messy
if
> there are hundreds of columns.
>
> Arbitrary data set and codes are shown below for your reference:
>
> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
>
> rownames(x) <- letters[1:dim(x)[1]]
>
>> x
> ?V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
> a ?0 ?1 ? 1 ? ?1 ? 0 ? 0 ? ?0 ? 0 ? 1 ? ?0
> b ?1 ?1 ? 1 ? ?1 ? 0 ? 1 ? ?0 ? 0 ? 1 ? ?1
> c ?0 ?1 ? 1 ? ?0 ? 0 ? 0 ? ?0 ? 0 ? 0 ? ?1
> d ?1 ?0 ? 0 ? ?1 ? 1 ? 1 ? ?1 ? 1 ? 0 ? ?0
> e ?1 ?0 ? 0 ? ?0 ? 0 ? 1 ? ?1 ? 0 ? 1 ? ?0
>
> V1.ind <- rownames(x)[x[,"V1"]==1]
> V2.ind <- rownames(x)[x[,"V2"]==1]
> V3.ind <- rownames(x)[x[,"V3"]==1]
> V4.ind <- rownames(x)[x[,"V4"]==1]
> :
> :
> V10.ind <- rownames(x)[x[,"V10"]==1]
>
>> V1.ind
> [1] "b" "d" "e"
>> V2.ind
> [1] "a" "b" "c"
>> V3.ind
> [1] "a" "b" "c"
> :
> :
>> V10.ind
> [1] "b" "c"
>
>
>
> Your expertise in resolving this issue would be highly appreciated.
>
>
> Steve
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

Henrique Dallazuanna

2009-Aug-27 12:10 UTC

head link

[R] Help on efficiency/vectorization

Try this also:

lapply(apply(x == 1, 2, which), names)

On Thu, Aug 27, 2009 at 3:13 AM, Steven Kang
<stochastickang@gmail.com>wrote:
> Dear R users,
>
> I am trying to extract the rownames of a data set for which each columns
> meet a certain criteria. (condition - elements of each column to be equal
> 1)
>
> I have the correct result, however I am seeking for more efficient (desire
> vectorization) way in implementing such problem as it can get quite messy
> if
> there are hundreds of columns.
>
> Arbitrary data set and codes are shown below for your reference:
>
> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
>
> rownames(x) <- letters[1:dim(x)[1]]
>
> > x
>  V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
> a  0  1   1    1   0   0    0   0   1    0
> b  1  1   1    1   0   1    0   0   1    1
> c  0  1   1    0   0   0    0   0   0    1
> d  1  0   0    1   1   1    1   1   0    0
> e  1  0   0    0   0   1    1   0   1    0
>
> V1.ind <- rownames(x)[x[,"V1"]==1]
> V2.ind <- rownames(x)[x[,"V2"]==1]
> V3.ind <- rownames(x)[x[,"V3"]==1]
> V4.ind <- rownames(x)[x[,"V4"]==1]
> :
> :
> V10.ind <- rownames(x)[x[,"V10"]==1]
>
> > V1.ind
> [1] "b" "d" "e"
> > V2.ind
> [1] "a" "b" "c"
> > V3.ind
> [1] "a" "b" "c"
> :
> :
> > V10.ind
> [1] "b" "c"
>
>
>
> Your expertise in resolving this issue would be highly appreciated.
>
>
> Steve
>
>        [[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.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

Martin Maechler

2009-Aug-27 12:33 UTC

head link

[R] Help on efficiency/vectorization

>>>>> "MO" == Moshe Olshansky <m_olshansky at
yahoo.com>
>>>>>     on Wed, 26 Aug 2009 23:36:22 -0700 (PDT) writes:
    MO> You can do
    MO> for (i in 1:ncol(x)) {names <-
rownames(x)[which(x[,i]==1)];eval(parse(text=paste("V",i,".ind<-names",sep="")));}

you can, but after   install.packages("fortunes")

  > require("fortunes")
  > fortune("parse")

  If the answer is parse() you should usually rethink the question.
     -- Thomas Lumley
	R-help (February 2005)


So please use one of the other answers given in the thread...


    MO> --- On Thu, 27/8/09, Steven Kang <stochastickang at gmail.com>
wrote:

    >> From: Steven Kang <stochastickang at gmail.com>
    >> Subject: [R] Help on efficiency/vectorization
    >> To: r-help at r-project.org
    >> Received: Thursday, 27 August, 2009, 4:13 PM
    >> Dear R users,
    >> 
    >> I am trying to extract the rownames of a data set for which
    >> each columns
    >> meet a certain criteria. (condition - elements of each
    >> column to be equal
    >> 1)
    >> 
    >> I have the correct result, however I am seeking for more
    >> efficient (desire
    >> vectorization) way in implementing such problem as it can
    >> get quite messy if
    >> there are hundreds of columns.
    >> 
    >> Arbitrary data set and codes are shown below for your
    >> reference:
    >> 
    >> x <- as.data.frame(matrix(round(runif(50),0),nrow=5))
    >> 
    >> rownames(x) <- letters[1:dim(x)[1]]
    >> 
    >> > x
    >> ? V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
    >> a? 0? 1???1? ?
    >> 1???0???0? ?
    >> 0???0???1? ? 0
    >> b? 1? 1???1? ?
    >> 1???0???1? ?
    >> 0???0???1? ? 1
    >> c? 0? 1???1? ?
    >> 0???0???0? ?
    >> 0???0???0? ? 1
    >> d? 1? 0???0? ?
    >> 1???1???1? ?
    >> 1???1???0? ? 0
    >> e? 1? 0???0? ?
    >> 0???0???1? ?
    >> 1???0???1? ? 0
    >> 
    >> V1.ind <- rownames(x)[x[,"V1"]==1]
    >> V2.ind <- rownames(x)[x[,"V2"]==1]
    >> V3.ind <- rownames(x)[x[,"V3"]==1]
    >> V4.ind <- rownames(x)[x[,"V4"]==1]
    >> :
    >> :
    >> V10.ind <- rownames(x)[x[,"V10"]==1]
    >> 
    >> > V1.ind
    >> [1] "b" "d" "e"
    >> > V2.ind
    >> [1] "a" "b" "c"
    >> > V3.ind
    >> [1] "a" "b" "c"
    >> :
    >> :
    >> > V10.ind
    >> [1] "b" "c"
    >> 
    >> 
    >> 
    >> Your expertise in resolving this issue would be highly
    >> appreciated.
    >> 
    >> 
    >> Steve
    >> 
    >> ??? [[alternative HTML version deleted]]
    >> 
    >> ______________________________________________
    >> R-help at 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.
    >> 

    MO> ______________________________________________
    MO> R-help at r-project.org mailing list
    MO> https://stat.ethz.ch/mailman/listinfo/r-help
    MO> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
    MO> and provide commented, minimal, self-contained, reproducible code.

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