On May 11, 2010, at 9:08 PM, David Winsemius wrote:
On May 11, 2010, at 8:38 PM, Noah Silverman wrote:
Hi,
An example data set is:
group level color
A 1 "blue"
A 1 "Red"
B 1 "blue"
B 2 "Red"
A 2 "Red"
B 2 "Red"
B 2 "blue"
B 2 "blue"
A 2 "blue"
A 2 "Red"
I'd like to compute a summary of counts for each combination of
group, level, color.
An example output would be something like this:
group level color count
A 1 "blue" 1
A 2 "red" 2
B 2 "red" 2
etc..
The tapply function seems to do this for a single variable, but I
can figure out to to do it for combinations of more than one factor.
This doesn't work?
tapply(example$color, c(example$group, example$level), length)
I guess not. so perhaps:
as.data.frame( table(example) )
--
David
I also see the ave function, but can't figure out how to apply it
to multiple factors.
It would give you as many lines as in the original which is not what
you want.
--
David,
Any suggestions?
Thanks
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David Winsemius, MD
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______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
