[R] Function for subset of cases/lines

Stefan Uhmann stefan.uhmann at mailbox.tu-dresden.de
Thu May 15 10:53:29 CEST 2008


Dear Dimitris, dear Matthias,

thank you very much, I adapted the short solution you both provided - 
works as intended. And I have learned sth. once again.

Regards,
Stefan

Dimitris Rizopoulos schrieb:
> 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.
>>
> 
> 
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> 
>



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