I want a list of the number of times some factor levels appear together,
similar to the following SQL statement:
SELECT A, B, COUNT(C) FROM TBL GROUP BY A, B
How do I do that with a data.frame in R?
Thanks,
Jesper Frickmann
Statistician, Quality Control
Novozymes North America Inc.
77 Perry Chapel Church Road
Franklinton, NC 27525
USA
Tel. +1 919 494 3266
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