diffs <- do.call(expand.grid, dt) diffs$delta <- rowSums(expand.grid(dt$a, -dt$b)) ------------------------------------------------------------------- Jacques VESLOT
CNRS UMR 8090 I.B.L (2ème étage) 1 rue du Professeur Calmette B.P. 245 59019 Lille Cedex Tel : 33 (0)3.20.87.10.44 Fax : 33 (0)3.20.87.10.31 http://www-good.ibl.fr ------------------------------------------------------------------- Arun Kumar Saha a écrit : > Dear R Users, > > Suppose I have a dataset like this: > > a b > > 39700 485.00 > 39300 485.00 > 39100 480.00 > 38800 487.00 > 38800 492.00 > 39300 507.00 > 39500 493.00 > 39400 494.00 > 39500 494.00 > 39100 494.00 > 39200 490.00 > > Now I want get a-b for all possible combinations of a and b. Using two 'for' > loop it is easy to calculate. But problem arises when row length of the data > set is large eg. 1000 or more. Then R takes lot of time to do that. Can > anyone please tell me whether there is any R-function to do such kind of job > quickly? > > Thanks and regards, > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. > ______________________________________________ [email protected] 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.
