[R] selections of data by one variable

[Dimitris Rizopoulos]

try this:

d <- data.frame(a=1:10, b=11:20)
e <- c(13, 15, 17)
##############
d. <- subset(d, b %in% e)
d.


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



----- Original Message ----- 
From: "Tu Yu-Kang" <yukangtu at hotmail.com>
To: <R-help at stat.math.ethz.ch>
Sent: Wednesday, May 04, 2005 1:14 PM
Subject: [R] selections of data by one variable


> Dear R experts,
>
> My problem is as follows:
>
> Suppose I have a data frame d comprising two variable a<-c(1:10) & 
> b<-c(11:20).
>
> I now want to select a subgroup according the values of b.
>
> I know if I just want to select, say, b=17, I can use f<-d[d$b==17] 
> and R will give me
>> f
>  a  b
> 7 7 17
>
> However, if now I want to select a subgroup according to 
> b==e<-c(13,15,17), then the same syntx doesn't work.
>
> What is the correct way to do it?  My data have more than one 
> million subjects, and I want to select part of them according to 
> their id numbers.
>
> Your help will be highly appreciated.
>
> Best regards,
>
> Yu-Kang
>
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