[R] Function for subset of cases/lines

[Dimitris Rizopoulos]

try this:

q1 <- c(4660,5621,5629,8030,8080,8180,8501,8190,8370,8200)

dat <- read.table(textConnection(
"number height
1 4660  2.5
2 5010  1.4
3 5621  0.8
4 5629  2.3
5 8030  2.5
6 8080  2.4
7 8090  0.9
8 8180  1.4
9 8501  1.2
10 8190 1.9
11 8200 2.0
12 8370 2.1
13 8200 1.8"), header = TRUE)
closeAllConnections()

mean(with(dat, height[number %in% q1]))
# or
mean(dat$height[dat$number %in% q1])


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
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


----- Original Message ----- 
From: "Stefan Uhmann" <stefan.uhmann at mailbox.tu-dresden.de>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, May 15, 2008 10:07 AM
Subject: [R] Function for subset of cases/lines


> Hi,
>
> I have a vector:
>
> q1<-c(4660,5621,5629,8030,8080,8180,8501,8190,8370,8200)
>
> The following command gives me the mean of its elements:
>
> mean(q1)
> [1] 7346.1
>
> What can I do to do the same for the variable 'height', but only for 
> the cases/rows which have one of the elements of q1 as 'number':
>
>   number height
> 1 4660 2.5
> 2 5010 1.4
> 3 5621 0.8
> 4 5629 2.3
> 5 8030 2.5
> 6 8080 2.4
> 7 8090 0.9
> 8 8180 1.4
> 9 8501 1.2
> 10 8190 1.9
> 11 8200 2.0
> 12 8370 2.1
> 13 8200 1.8
>
> Thanks for any help,
> Stefan
>
> ______________________________________________
> 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.
> 


Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm