[R] create matrix from comparing two vectors

Dimitris Rizopoulos Dimitris.Rizopoulos at med.kuleuven.be
Tue Jun 26 20:48:40 CEST 2007


try this:

test <- 1:10
fac <- c(3, 6, 9)

outer(test, fac, "<") * 1


I hope it helps.

Best,
Dimitris

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

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
      http://www.student.kuleuven.be/~m0390867/dimitris.htm


Quoting Van Campenhout Bjorn <bjorn.vancampenhout at ua.ac.be>:

> hi all, sorry for this basic question, I think I know I should use   
> ?apply, but it is really confusing me...
>
> I want to create a matrix by comparing two vectors.  Eg:
>
> test<-seq(1:10)
> fac<-c(3,6,9)
>
> and i want to end up with a 10*3 matrix with a boolean that tests if  
>  test<fac, so something like:
>
> 1 1 1
> 1 1 1
> 0 1 1
> 0 1 1
> 0 1 1
> 0 0 1
> 0 0 1
> 0 0 1
> 0 0 0
> 0 0 0
>
> I can't find the solution without using a loop...
>
> B
>
> 	[[alternative HTML version deleted]]
>
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