Re: [R] Vector comparison to matrix

From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>
Date: Tue 16 Aug 2005 - 21:20:01 EST

or maybe something like this:

nMatches2 <- sum(!is.na( match(apply(A, 1, paste, collapse = ""), paste(target, collapse = "")) ))

Best,
Dimitris



Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium

Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


Hi Todd and list,

I see you have received a few suggestions, here's another:

# set up data: your vector and an a 3x300000 matrix with a few
# matching lines:

target<-c(1,2,3)
A<-matrix(sample(1:3,300000,replace=TRUE),ncol=3)

# count matches:

nMatches<-sum(apply(A,1,function(x,target)   all.equal(x,target),target)=="TRUE")

# by applying a simple function, which takes 'target' as an 'extra'
# argument, to the rows of A. The function returns a vector of
# differences and 'TRUE'-s, the latter of which can be counted.

This took 1-2 minutes on my >3 year old laptop.

Siggi

> version

         _
platform i686-redhat-linux-gnu

arch     i686
os       linux-gnu

system i686, linux-gnu
status
major 2
minor 0.0
year 2004
month 10
day 04
language R

Yeah, I know, an update is (over)due.

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Received on Tue Aug 16 21:23:12 2005

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