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Applying a function to all combinations of factors
2 messages · Marc Belisle, Jean Eid
you could use something like by(data, list(data1$day, data1$hour), function(x) cor(x[,"var1"], x[, "var2"])) This will return a list and then you can unlist and turn to matrix HTH
Is there a way to apply a function, say cor(), to each combination of some number of variables, and this, without using loops? For example, I have day, hour, var1 and var2. How could I compute cor(var1,var2) for each day*hour combination and obtain a matrix with day, hour and the cor value for each combination? Thanks for your time, Marc ==================Marc B?lisle Professeur adjoint Chaire de recherche du Canada en ?cologie spatiale et en ?cologie du paysage D?partement de biologie Universit? de Sherbrooke 2500 Boul. de l'Universit? Sherbrooke, Qu?bec J1K 2R1 Canada T?l: +1-819-821-8000 poste 1313 Fax: +1-819-821-8049 Courri?l: Marc.M.Belisle at USherbrooke.ca [[alternative HTML version deleted]]
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