Hi,
as an R-beginner, I have a recoding problem and hope you can help me:
I am working on a SPSS dataset, which I loaded into R (load("C:/...)
I have 2 existing Variables: "ID" and "X" ,
and one variable to be computed: meanX.dependID (=mean of X for all rows
in which ID has the same value)
ID = subject ID. Since it is a longitudinal dataset, there are repeated
measurement points for each subject, each of which appears in a new row.
So, each ID value appears in many rows. (e.g. ID ==1 in row 1:5; ID ==2
in rows 6:8 etc).
Now: For all rows, in which ID has a certain value, meanX.dependID shall
be the mean of X in for these rows. How can I automatisize that, without
having to specify the number of the rows each time?
e.g.
ID X meanX.dependID
1 2 2.25
1 3 2.25
1 1 2.25
1 3 2.25
2 5 3.3
2 2 3.3
2 3 3.3
3 4 3
3 1 3
3 2 3
3 3 3
3 4 3
3 5 3
Thanks a lot! Hope this is the right place to post, if not, please tell me!
best,
Julia
______________________________________________
R-help@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.
