It may be possible to do this in a single step, but
> x1 <- aggregate(response~id+age, data, mean)
> x2 <- data[data$eye=="l", c("id", "response2")]
> merge(x1, x2)
id age response response2
1 1 2 4.60 High
2 2 9 2.65 High
3 3 5 3.65 High
4 4 2 7.55 High
5 5 11 4.15 High
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of Tom Wright
Sent: Thursday, March 27, 2014 3:48 PM
To: r-help@r-project.org
Subject: [R] summarizing a dataset on a factor
Hi all,
I've spent too long in matlab land recently and seem to have
forgotten
my R skillz ;-)
I'm sure I'm missing a simple way to do this...
Given a data frame
id<-rep(1:5,2)
eye<-c(rep('l',5),rep('r',5))
age<-rep(round(runif(5,0,12)),2)
response<-round(runif(10,1,10)*10)/10
response2<-sample(c('High','Low'),10,replace=TRUE)
data<-data.frame(id,eye,age,response,response2)
I want to create a new dataset averaging the response variable
from both
eyes for each test.
I know there are many ways to do this but... I would also like
to keep
the value of the response2 variable for the left eye.
ending up with the dataset
id age response response2
1 9 3.65 High
2 10 3.85 High
3 8 8.15 Low
4 4 4.4 Low
5 0 4.6 High
I thought something like
f<-function(x){#make my choices here}
aggregate(data,list(data$id),f)
but x only seems to contain the first column of data.
I could probably have done this manually in the time spent
writing this
email.
any help appreciated,
Tom
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and provide commented, minimal, self-contained, reproducible code.
